We get a lot of emails every week from our extreme sports customers asking why we don’t keep the Red, Blue and Green Grade Thermalutions in stock.

Short answer: We want our customers to be happy; we believe you will be more happy with one of the three thermalutions we do keep in stock: Surf SeriesCompact Dive Series and Yellow Grade.  

The breakdown:

Green Grade Vs Surf Series 15M: The Thermalution Green Grade is comparable to our Surf Series suit.  Both models are designed for shallow water activities, such as surfing, kiteboarding, wakeboarding, and shallow water scuba or freediving. 

Battery Power:

Green Grade: One 14.8 volt lithium polymer battery.
Surf Series: Two 7.4 volt lithium polymer batteries. 

Battery Life 

Green Grade: 90 – 120 minutes
Surf Series: 90 – 150 minutes

Depth Rating

Green Grade: 30 feet
Surf Series: 75 feet

THE BOTTOM LINE: The Green Grade Suit uses one battery, twice as thick as the two batteries found in the Surf Series suit.  The majority of our surfing customers find that the Green Grade battery is too thick and interfered with paddling while surfing.   Also, this battery is too thick to be used beneath a kiteboarding or windsurfing harness and can put an uncomfortable pressure on the ribs while riding using a harness.  The Surf Series suit was designed with two batteries (Each Half the Thickness) in order to provide the user with a comfortable, thin and sleek battery that stays out of the way and unnoticed while you enjoy being warm on the water.  

With a slightly longer battery life, twice the depth rating, and batteries designed specifically for high-impact performance sports, we recommend the 15M Surf Series over the Green Grade.

Blue Grade Vs Compact Dive Series 70M: The Thermalution Blue Grade is comparable to the Compact Dive Series suit. Both models are designed with the recreational scuba diver in mind. Both suits are almost identical. The biggest differences are in the controller used to change the temperature of the suit and the depth rating held by each of the two models. 

Battery Power

Blue Grade: Two 7.4 volt lithium polymer batteries
Compact Dive Series: Two 7.4 volt lithium polymer batteries

Battery Life

Blue Grade: 90 – 120 minutes
Compact Dive Series: 90 – 150 minutes

Depth Rating:

Green Grade: 150 feet
Compact Dive Series: 230 feet


BLUE Grade: Close Proximity Sensor.  Basically, the Blue Gsuit works using a very similar wired controller coming out of the shoulder of the Thermalution combined with a magnetic wrist watch.  The wrist watch must be touched to the controller unit for small periods of time in order to change the temperature and/or turn the suit on and off.  The wrist watch must TOUCH the controller unit and be held together for one second to change the temperature or three seconds to turn the suit on and off.   

The Compact Dive Series model is designed for the scuba diver who does not want to use both hands to change the temperature of their suit.  It was designed using a more simple design, which does not use the magnetic wrist watch controller found in the Blue Grade.  Rather than using magnets and an added wrist watch, and simply adds a sliding button to the end of the shoulder controller, enabling the user to change the temperature of their wetsuit using only one hand and the simple push of a button. 

THE BOTTOM LINE:  With its deeper depth rating and one-handed temperature control, We recommend the Compact Dive Series over the Blue Grade Thermalution!   

Red Grade vs Yellow Grade Thermalution: The Thermalution Red Grade is an undergarment designed to use ONLY under a drysuit.  The material is similar to that of thermal underwear or drysuit thermal undergarments.  The suit is very similar to the Yellow Grade vest, in that both models use the same double-sized 14.8V batteries and the wireless controller unit, compatible with a drysuit. 

Battery Power

Red Grade Thermalution: Two 14.8 volt lithium polymer batteries
Yellow Grade Thermalution: Two 14.8 volt lithium polymer batteries

Battery Life

Red Grade Thermalution: 180 – 240 minutes
Yellow Grade Thermalution: 180 – 240 minutes

Depth Rating:

Red Grade Thermalution: 300 feet
Yellow Grade Thermalution: 300 feet


Both suits use the Thermalution wireless controller with push button temperature control found on a wireless wrist watch. 

THE BOTTOM LINEThe Yellow Grade Thermalution and Red Grade Thermalution both have the same great depth rating, the same battery power/life, the same heating area, and the same controller.  The Yellow Grade Thermalution, however, is compatible with a wetsuit AND drysuit, vs the Red Grade which is only compatible with dry suit scuba diving.  The Vast Majority of our customers do not dive strictly in drysuits, so this is the primary reason why we do not keep the Red Grade suit stocked in our store.  We recommend the Yellow Grade Thermalution if you do any wetsuit scuba diving during the year.  This lets you to get the most from your Thermalution, allowing you to use your Thermalution on every dive trip, even when the water isn’t quite cold enough to justify scuba diving with your dry suit.