Tattoo Machine Replacement Coils. Make Sure your coils will fit correctly. Measurements are located below. Available in: 8-Wrap size: 3.25cm (H) x 3.5cm (W) 10-Wrap size: 3.0cm (H) x 3.5cm (W) What does it mean to have more wraps? The more wraps there are the more layers of copper are used. Therefore making a larger magnet which makes it a stronger machine.