Which Inflation System Is Right For Your Lifejacket?

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Choosing the right inflation system is one of the most important decisions you’ll make when buying a lifejacket. It shapes how quickly the jacket inflates, how much control you have in the water, and how it behaves in real‑world conditions.

 

This page breaks down the different TeamO‑fitted inflation systems, explains which firing head suits which sailor, and helps you decide which one aligns with the way you sail and the conditions you expect.

The Full Details

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As there's a lot of information about each type of inflation system, we've put it all into this drop-down section. Click the one you're interested in to see the information, or open them all to read everything.

Micro Manual Inflation System

HOW IT ACTIVATES: Pull‑to‑inflate toggle

BEST FOR: Wet‑deck sailing, spray‑heavy conditions, users who want full control

PROS: Very low risk of accidental inflation, simple mechanism

THINGS TO KNOW: Only inflates if you pull the toggle; not suitable if you may be unable to act

Manual gives you complete control over when the lifejacket inflates. Instead of relying on water or a sensor, you pull the toggle to trigger the CO₂ cylinder and inflate the jacket. Manual is often chosen by sailors who:

Spend a lot of time in very wet or spray‑heavy conditions.

Want to avoid accidental inflation from spray, rain, or deck wash.

Prefer a simple, straightforward mechanism.

What to know before choosing the Manual inflation system
 

The big advantage of Manual is the low‑risk of nuisance inflation. The limit is obvious: if you’re shocked, injured, or unable to pull the handle, the jacket will not inflate on its own.

 

Choose Manual when your priority is control and certainty, and when you’re comfortable with the responsibility of activating the jacket yourself.

ProSensor Elite (Automatic)

HOW IT ACTIVATES: Automatic water‑activated system

BEST FOR: Offshore, night sailing, higher‑risk situations

PROS: Inflates without you needing to act, strong all‑round automatic choice

THINGS TO KNOW: Must be kept in date and serviced regularly; will inflate when submerged

 

ProSensor Elite is an automatic inflation system that activates when the jacket and firing head are submerged in water. It’s designed to inflate the jacket without any action from the wearer, giving you an extra layer of protection in high‑risk situations.

Offshore and ocean sailors.

People who may be knocked overboard at speed.

Anyone who wants the jacket to act even if they’re injured, unconscious, or unable to pull a toggle.

What to know before choosing the ProSensor Elite inflation system
 

ProSensor Elite is a strong all‑round automatic choice, but it must be kept in date and serviced regularly. It will inflate when submerged, so it’s not designed to be used in wet conditions where you expect the jacket to be in the water frequently.

 

Choose ProSensor Elite if your priority is automatic safety and you’re happy to manage a dated, service‑dependent system.

Mk5i (Automatic, Selective)

HOW IT ACTIVATES: Automatic with selective trigger

BEST FOR: Very wet conditions where you still want automatic inflation

PROS: Lower risk of nuisance activation than standard automatics

THINGS TO KNOW: Still an automatic system; needs servicing and correct fit

 

M5Ki is an automatic inflation system that adds a more selective trigger, helping to reduce the risk of accidental activation from spray or light contact with water. It still inflates fully when the jacket is properly submerged.


M5Ki is popular with sailors who:

Want the safety of an automatic system.

Still expect to be in very wet conditions, where spray and deck water are common.

Want some protection against nuisance activation without moving away from automatic inflation.

What to know before choosing the MK5i inflation system
 

M5Ki gives you a more “calibrated” automatic response, but it’s still an automatic system that must be kept in date and in good condition. It’s not a substitute for wearing the jacket correctly or checking it before you go.

 

Choose M5Ki when your priority is automatic safety plus a more selective trigger.

Hammar (Hydrostatic Automatic)

HOW IT ACTIVATES: Hydrostatic automatic, activates only when properly submerged

BEST FOR: Wet, splash‑filled conditions where you want true automatic inflation

PROS: Very low risk of accidental inflation, simple mechanism

THINGS TO KNOW: Hydrostatic‑only trigger; must be serviced and replaced according to schedule

 

Hammar uses a hydrostatic automatic firing head that activates only when the jacket is submerged under a certain depth of water. It’s designed to ignore spray, rain, and light contact with the surface.


Hammar is often chosen by sailors who:

Want genuine automatic inflation in the water.

Are concerned about accidental activation from spray or deck water.

Frequently sail in very wet conditions but still want the confidence that the jacket will inflate if they go overboard.

What to know before choosing the Hammar inflation system
 

Hammar is one of the most spray‑resistant automatic systems, but it’s also a dated component that must be checked and replaced periodically. It’s not intended for use in shallow water or where the jacket will be deliberately submerged and re‑used.

 

Choose Hammar when your priority is automatic inflation with very low risk of nuisance activation.

Which TeamO Lifejacket Uses Which System?

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Micro

Micro Manual
Mk5i

Coastal

Micro Manual
Mk5i

Offshore

Manual 
ProSensor Elite
Hammar

Ocean

ProSensor Elite

Which TeamO Firing Head Should I Choose?

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Manual: Best if you want total control over inflation, are comfortable pulling the toggle yourself, and sail in very wet conditions where false activation would be a problem.

 

ProSensor Elite: Best if you want a straightforward automatic system that inflates when submerged and suits offshore, night, or higher‑risk sailing.

 

M5Ki: Best if you want automatic inflation but also want a bit more selectivity, so the system is less likely to fire from spray or light contact.

 

Hammar: Best if you want the lowest chance of accidental inflation from spray or deck water, while still getting true automatic inflation when you go overboard.

Safety, Fit, Service

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When your lifejacket has been deployed, the firing head will need to be re-armed. You can buy rearming kits from us, and inflation system rearming guides are here. 

 

If you're heading out on a lengthy ocean voyage, we recommend that you have an appropriate number of rearming kits on board with you - even if you're expecting calm waters. For those who are taking part in RORC races, make sure you've checked the race regulations and that you have both the appropriate lifejacket and have rearming kits available.

 

Of course, no lifejacket or the inflation system can be depended upon unless it has been suitably maintained. We recommend that TeamO lifejackets are professionally serviced every 12 months. You can book servicing for your TeamO lifejacket here. 

FAQs

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Which system is best for offshore sailing?

For offshore sailing, most people will want an automatic system, because it can inflate the lifejacket even if the wearer is unable to act. ProSensor Elite and Hammar are both strong choices depending on whether you want a water-activated or hydrostatic automatic system, while M5Ki is a good option if you want automatic inflation with a more selective trigger. The exception may be if you're in a boat where you have concerns about being restricted in a capsize situation. 

Is automatic or manual safer?

Neither system is universally “safer” - it depends on how you sail and what risks you’re trying to manage. Automatic systems are designed to inflate without action from the wearer, which is valuable if someone is injured or unconscious. Manual systems give you full control over inflation, which can be useful in wet conditions where you want to avoid accidental activation.

What is the difference between Hammar and M5Ki?

Both are automatic systems, but they work differently. Hammar is a hydrostatic system, which means it activates when the jacket is properly submerged rather than from spray or light water contact. M5Ki is also automatic, but it uses a different trigger design and is often chosen by sailors who want automatic inflation with a more selective response.

Can I convert from an automatic to a manual system?

In some cases, yes, but it depends on the specific lifejacket model and the parts available for it. Any change to the inflation system should be made using the correct compatible components and in line with the manufacturer’s guidance. 

 

We carry conversion kits for the ProSensor Elite and Mk5i inflation systems.

 

If you’re unsure, it’s best to check the jacket model and speak to us before making any changes.

How often should an inflation head be replaced?

Inflation heads should be replaced: 

  • According to the service schedule for that specific system
  • After any activation 
  • When the unit reaches its expiry date 

Even if the jacket has never been used, the firing head is a safety component and should be inspected and maintained regularly. Always follow the replacement interval marked on the component and the servicing guidance for the jacket.

Which TeamO lifejackets use each system?

Micro can be fitted with Micro Manual and Mk5i

Coastal can be fitted with Micro Manual and Mk5i 

Offshore can be fitted with UML Manual, ProSensor Elite, or Hammar

Ocean is fitted with ProSensor Elite as standard

Still Unsure?

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Tell us how and where you sail, and we’ll help you choose the right lifejacket inflation system for your needs. 

 

Contact us on tech@teamomarine.com or call us on +44 (0)1489 776000.