Features 1、Graduated Accuracy: The product consists of a accuracy caliper with two plates which overlap a portion of the length. The bottom plate is calibrated in millimeters and the top plate is transparent and marked with a cross shaped thin line cursor. 2、Testing Table: Crack monitoring gauges are used to control cracks in walls and how they evolve over the measurement time. Prime polymer with easy to read measurement grating. 3、Fixed Post: The redesigned fixing posts make it easy to fix the two pieces together without the need for glue. 4、Easy to Record: Provide a crack record sheet and secure with screws. The opening or closing of the crack can then be recorded on the record sheet. 5、Lightweight and Convenient: The product is made of prime acrylic plate is small and easy to carry, lightweight and easy to use. Specifications Item Type: Crack Monitor Product Material: Acrylic Use: Measuring Instrument Weight: 36g / 1.27oz Package List 2 x Crack Monitor 4 x Expansion Tube 4 x Screws 1 x Instruction Manual