Bosch 2608837138 SDS-Plus drill bit set 5.5mm to 10mm 5pce features: Bosch 2608837138 SDS-Plus drill bit set these 5x drills have been designed and manufactured to give tradesmen superb drilling through concrete, sizes of this set are 5.5mm, 6mm, 7mm, 8mm and 10mm. Features in the Design of these Bosch SDS-Plus drills include a centre tip that guides the drill at the start reducing the tendency to walk gives more accurate drilling, a geometrical Form of the 4 cutter head designed to prevent jamming and breakage during loaded drilling plus fast stock removal and increased drilling speeds due to the 4 flute drill Design Features Bosch SDS-plus-5X drill bits are specially designed with a centring tip for active and accurate centring in concrete. They have a 4-cutter geometry that.