This is a PTFE coated version of the 21045-A stainless-steel, 3-bladed paddle. The paddle is 2.5" (63.5 mm) in diameter and has a 5/16" (7.9 mm) diameter shaft. It is available with a length of 8.75 " (222 mm) , with maximum vessel size of 8" (203.2 mm). This is a high efficiency paddle for viscous liquids or semi-solids. It is compatible with all the stirrers and stir testers we carry, including the following series: GT31, GT24, HST10, ST20, HST20, and HST30.