High-quality ECG calipers: made of high-quality metal materials, used to measure ECG waveforms. Adjustable length: point can be adjusted to the required length as required, which is accurate and stable. Accurate measurement: A ruler is attached to the plastic protective cover for easy measurement reference. Adjustable tightness: adjustable screws are used to loosen and tighten the arm. Easy to carry: The protective cover with plastic clip is easy to fix on the nursing suit. Material:Metal colour:Blue Package Contents: 2 x ECG Calipers Only the above package content, other products are not included. Note: Light 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.