The Blunderbuss machine from www.tattooedpirate.com $225 and I know these work really well with no tuning or tinkering needed. Ideal for lining and color work. I have an artist in California who has the first set I built 3 years ago and the only thing he had to replace was one bearing after 2 years. Perfect linear motion and a long stroke of 4.2mm to power any size needle grouping. The Pirate