OTTO Stretcher System 22x30OTTO Watercolor Paper Stretcher uses a unique system of poplar clamp bars, stainless steel screws and t-nuts to stretch paper without tape marks or staple holes. Designed for use with 1/2" panels (it's shown with the Incredible Art Board-not included), it comes in three sizes for quarter, half and full size watercolor sheets.
Wet paper, align it on the board, place the bars around the edges, then tighten the screws with the included t-wrench and let dry. It's easy and effective, and leaves your paper undamaged.