The stand-up toggle holds blocks upright and allows attachment of control blocks. Toggle includes a 5/16" (8 mm) mainsheet block pin that accepts Midrange blocks, 57 mm double and triple AirBlocks and 75 mm single Black Magic AirBlocks. To attach Carbo control blocks to the stand-up toggle, choose 3163, 3165 cars or 598, 669 toggles. Fits: Midrange and 75 mm Black Magic blocks