Closed-Cell Foam Pads
Fourteen ounces, sixty dollars, no valve, no seams and nothing that can fail in the rain at midnight. Foam pads give up comfort and packability and give back total reliability, and they have a second career that is arguably more important than the first: stacked under an inflatable, a foam pad adds roughly two points of R-value and takes the puncture that would otherwise end a winter trip. R-values add when pads are stacked, which makes the cheapest item in this catalogue also the cheapest route to a winter-capable sleep system.
2 of them here from 2 makers, priced $60 to $60. The best warmth-per-ounce of the group is the Therm-a-Rest Z Lite Sol at 0.14 R per ounce. The lightest is the Therm-a-Rest Z Lite Sol at 14 oz, and the cheapest is the Therm-a-Rest Z Lite Sol at ~$60.
Therm-a-Rest
Therm-a-Rest Z Lite Sol
An accordion of dimpled foam that cannot be punctured, cannot leak, needs no valve and weighs 14 ounces. R-value 2 is genuinely marginal on its own once the ground drops below about 40 °F, and the three-quarter-inch thickness means hips and shoulders feel the ground — but nothing else in the catalogue is this indestructible or this cheap, and its second career is as the layer people put under an inflatable pad in winter to add roughly two points of R-value and protect the fabric. It also folds flat into a sit pad, a pack frame, and a splint, which is why it never quite leaves anyone's kit.
Best for: Foam sleepers, winter layering under an air pad, and anyone tired of leaks
Full spec sheet
NEMO
NEMO Switchback
The direct competitor to the Z Lite Sol, and the one with slightly deeper nodes — 0.9 inches against 0.75 — which is the whole argument between them. Same R-value of 2, same accordion fold, same complete immunity to punctures. The dual-density foam is firmer underneath and softer on top, and the hexagonal node pattern traps a little more air than the Therm-a-Rest's dimples. Half an ounce heavier and a shade more expensive; whether the extra loft is worth it is a genuinely close call.
Best for: Foam sleepers and as a winter layer under an air pad
Full spec sheet