BLI Machine Trowel Blades Combination 4pkBetonelli combination machine trowel plades, 4 pk. Combination blades are designed for operators who wish to use one blade for both floating and finishing applications. During the initial stages of power trowelling, the blades is set flat and used for floating, as the slab firms up the blade pitch is increased to produce a smooth finish. BN20479 BN20480 Fits machine: BN436 BN440 BN446 Size (mm): 205 x 355 205 x 455 Size (in): 8 x 14 8 x 18 Weight