Steel Shank The steel shank style cup is designed to follow tooth contours with flex and flare, making it ideal for polishing lingual and interproximal areas. Soft or firm; Long; Ribbed Interior; Smooth Exterior; Latch-Type. Screw Type The screw-type cup is designed to follow the natural contours of the teeth for maximum surface contact, minimal splatter, and effective stain removal. Soft or firm; Long; Webbed Interior; Smooth Exterior; Screw-Type. Snap-On The snap-on cup is designed to deliver more prophy paste to the tooth surface for efficient stain and biofilm removal. Soft or firm; Long; Webbed Interior; Smooth Exterior; Snap-On; Latex-Free.