WTB ISO Insulated Pants
Probably a men’s medium (31/32W, 32-34L).
Most things on this list: https://www.backcountry.com/mens-insulated-pants
especially Mountain Hardwear Compressor, MHW Highball Insulated, Patagonia Nano Puff, BD Stance, NF Thermoball. Synthetic preferred (going to be primarily belay pants for ice climbing / camp pants).
