Makes it easier to fine focus while looking through grain magnifier, especially when making larger prints. 24" long extension shaft, connected to adapter via coil joint, allows full range of movement. Precision engineered, non-slip adapter fits over fine focus knob on all Saunders/LPL 4 x 5" enlargers. Also works on Saunders/LPL 670-series enlargers fitted with optional fine focusing attachment (Cat. No. 240-300) Also works with all Saunders/LPL 4 x 5" enlargers.