Casper Kiser who has has decades sharpening as a manufacturer and as a in-salon sharpener shares his expertise on understanding the relationship between the tension, edge and alignment in the sharpening and cutting of a shear. The 50 minute DVD is an edited version of a 2+ hour presentation at the 2011 Sharpeners Jam in Atlanta, GA. The DVD is filmed on location in front of a live audience. The clip here is concerning a discussion on the 800 mm radius in answer to a question posed by a sharpener will give you a taste of the video. The lighting is not the best, but you will clearly see the power point presentation as it is superimposed over the video. This is invaluable information to any shear or scissor sharpener.