1. Two different chuck systems for cordless drill.

    1) A double-sleeve keyless chuck: this takes two hands to operate it. You have to firmly hold one part of the chuck, while turning the other part to open/close the chuck.
  2. 2) A single-sleeve keyless chuck: this is the most convenient option because you only need one hand to operate it, leaving one hand free to hold either the tool or the accessory.