S, M and L stands for different height, A and B ball head can mo unt 1107 stand. 1107 series pipe stands equip lock ring allowing quick height adjustment. Foldable structure, easy for transportation and stock. Durable V-head, easy to install, for 1/8"-12"(3mm-300mm), suitable in many applications,Like pipe threading, cutting, grooving etc. A portable handle wrapped by rubber is also a highlight. Easy carrying and storage.