Recommended clothing in the Arctic: Woolen underwear as the base layer, warm wool or flees trousers & sweater on the top, two layers of socks (thin & thick woolen socks), windproof layer on the top (Spacious clothing is recommended since air is the best insulation), gloves (wool is recommended), warm hat (wind proof), scarf or flees- tube
Good to have with you: Indoor shoes or extra woolen socks, Indoor leisure wear/ casual clothing for dinner, toilet articles, Sunglasses, sunscreen (not based on water), binoculars, camera, ccontact lenses (for those using glasses), small bag/ backpack for personal equipment during the trip, rest of your belongings you can leave to Basecamp Hotel.
Try to pack in couple of small bags, rather than one big one due to the slim size of the sled. Waterproof bags are a good option. Do note that you need to pack some of the common equipment’s to your sledge as well, so space is quite limited.