SDS-Plus
Affiliate link — we may earn a commissionSDS-Plus is a bit retention system used on rotary hammers. The shank has two open grooves and two closed grooves that lock into the chuck with a twist, no tightening required. The grooves let the bit slide back and forth slightly, which is necessary for the hammering action. SDS-Plus is the standard for light to mid-duty rotary hammers (bits up to about 1-1/8-inch diameter). SDS-Max is the larger version for heavy-duty demolition hammers (bits from 1/2-inch up to 2 inches). The two systems aren't compatible. You can't put an SDS-Max bit in an SDS-Plus tool or vice versa.
Why It Matters
If you're drilling into concrete, brick, or block, a rotary hammer with SDS-Plus bits does the job 5 to 10 times faster than a hammer drill with standard bits. The SDS chuck also eliminates bit slippage under heavy hammering. For anchors, tapcons, and concrete fasteners, this is the tool system that works.