The ultimate in ­thermal protection, ­drysuits come in two basic types: neoprene and bi- or ­trilaminate. Neoprene suits are stretchier, offering a snug fit with a good range of motion. Their thermal protection comes primarily from the insulating ability of the neoprene itself; most don’t require thermal undergarments. Bilam or trilam suits are lightweight, have no inherent buoyancy and don’t compress at depth. Designed solely to keep water out, the insulation that keeps you warm comes from what you wear as your undergarment. Drysuits are not as complicated as they look, but it will take a few dives to dial in your weighting, thickness of undergarment and other nuances of your particular suit. The bottom line: If you’re a cold-water diver, you know that nothing beats being warm underwater.

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This high-density 4 mm ­neoprene drysuit has its own thermal properties, so you don’t need to wear a thick undergarment. The ­neoprene also resists compression, so less ballast weight is required. The suit’s blind-stitched seams are ­neoprene-taped on the inside to add strength and enhance comfort. The shoulders and kneepads are reinforced for protection against abrasions. The suit comes with semi-rigid boots that can be turned inside out to facilitate ­drying after diving, and a roomy, ­expandable cargo pocket.

Contact: seacusa.com

Virtually bulletproof, the ­heavy-duty trilaminate DX-300X is built for technical divers and ­demanding dive conditions. The suit is also loaded with ­convenience features like double-thick kneepads, ­neoprene socks and suspenders. SiTech silicone neck and wrist seals allow for comfort and quick replacement, and each large thigh pocket has a Velcro closure and 2-inch D-ring. The “bias” cut and telescopic torso provides excellent freedom of movement.

Contact: hollis.com

Cold-water divers will find the Arc Tec 2.0 the perfect travel companion. Built to be lightweight, and fitted with flexible thermo socks with reinforced soles, the suit folds into a compact bundle of only 20-by-15 inches. Its 360-degree, YKK BDM dry front zipper also makes it easy to get into by yourself. Camaro added neoprene cuffs over the latex arm and leg seals to help increase warmth. The suspender system dials in fit and ­controls the suit when unzipped ­between dives.

Contact: camaro.at

Now available in a ­slimmer cut for female divers, the durable yet lightweight ­X-Mission was designed by Bare in collaboration with tec-diving experts. And it shows. Loaded with features, this trilaminate suit comes with attached boots, latex seals and a diagonal front zipper for easy self-donning; a pair of bellowed cargo pockets are provided for carrying tools. A crotch strap and suspenders are included, plus you’ll love the removable, noncompressible backer pad behind the inflater valve — it creates a comfortable buffer between your chest and the inflater valve.

Contact: baresports.com

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• How to maintain your drysuit

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