Cordless SDS Drill
SDS Hammer drills are similar to Hammer Drills in that they also pound the drill bit in and out while it's spinning. To make them more powerful they use a piston mechanism instead of a special clutch enabling them to deliver a much more powerful hammer blow than traditional Hammer Drills - they are able to drill larger holes much faster.
there are two types of SDS drills. SDS Plus and SDS Max the differenec lies in terms of size. SDS Plus bits are generally thinner and smaller than SDS Max bits. ... Thinner SDS Plus is generally for lighter duty work--mostly for drilling smaller holes; SDS Max is for heavier duty work--for drilling larger holes