Stainless Steel Propeller Paddle With Flat Holes For Benchmark 20L and 40L Overhead Stirrers, 1/EA. Enhance your laboratory mixing capabilities with the Benchmark Scientific Optional Propeller. Crafted from high-quality stainless steel, this propeller features flat holes for efficient mixing. Compatible with Benchmark Scientific overhead stirrers, this accessory is essential for various laboratory applications requiring precise and uniform mixing. Upgrade your equipment effortlessly and ensure reliable performance with the Benchmark Scientific Optional Propeller.