These screen printing hinge clamps are made of zinc alloy, chrome-coated surface, they are durable and rust resistant.They are used to secure your screen frame to a table or work surface, easy to install and positive locking compatible with perfect registration.The clamps feature two holes that you screw directly into your workbench and wide-wing thumb screws to secure your framecompatible with starters, new beginners to learn how to screen printing. The screen printing hinge clamp is the fastest way to build a printing press.The screen print butterfly clamps are used compatible with fixing screens when printing. It can hold all wood or metal screens from 0.5 inch to 1.8 inch (12 to 45 mm) thick, Height: 3.3 inch (85mm), Length of Clamp: 2.4 inch (60mm)Used compatible with fixing screens when printing, Making screen printing so much easier How to use:1--Take a flat wooden board and draw a straight line on the board.2--Take two points in a straight line, fitted with butterfly clip, according to the need to install a parallel or a few pairs.3--Installed on the screen, good printing position, locking chuck, flip up and down, flexible and unobstructed screen, you can put into use.Specifications:Material: metalColor: SilverSurface Treatment: chrome-platedParameters Application Thickness of Screen: below 1.77 inch (45mm)Package Contents:4 x Butterfly Hinge ClampsOnly the above package content, other products are not included.Note: Light shooting and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.