OSE H Series Cleaver 2 Blade Propellers, Machined out of Stainless Steel. CNC Computer machined to a high tolerance for use out of the box. No modifications are needed. Specs: Diameter 48mm Rotation: Left and Right pair (See picture) 1.6 Inch pitch ratio. Shaft Size 3/16" (4.75mm).NOTE: When used with Zonda GT or similar powered, these are high amp draw. These are for a few seconds use for drag style use. These will push parts hard. If you are worried about burning things up, these are NOT the props for you. Go smaller or stay stock.