The Rosco Strobist Collection is a 55-Piece filter kit that has most, if not all, the color filters you will ever need for your shoe-mount flash. Each filter is sized perfectly (38mm x 82mm) for most portable flash units. Working with David Hobby, founder of www.strobist.com, Rosco put together this collection of 20 different colors (including different strengths of several colours) for a total of 55 gels that cover nearly every situation where you need to filter your shoe-mount flash.