This is a snowbasket for mountain trekking. Sold as a pair Screw-On. PB-58 [Compatible models] Shinano Japanese trekking poles; Synano folder FREE, FADER FP Synano free FAST, Free FAST-α, Free SV-LT plastic, outer diameter 3.5 inches (90 mm), approx. 0.5 oz (15 g) basket (screw-in).