This optional Dowelmax 1/8" spacer plate enables centering for Dowelmax Classic and Dowelmax Jr. doweling jigs on 1" thick work pieces. It also allows for different offset options when used in combination with other Dowelmax spacers.Technical Details:Components are made of top quality aluminumPrecision-machined to a tolerance of 0.002"Requires Dowelmax Classic or Dowelmax Jr. doweling jig