Designed to adjust arrows level and bowstring verticality. Place arrow on rest, snap arrow on string, and move arrow up or down until level. String level checks vertical and horizontal position of bow for nock and sight installation. With high accuracy, providing you precisie level for archery. Made of plastic, with lightweight, sturdy and durable. Compact and portable, easy and convenient to carry. Fit for compound bows. Color: show as pictures. Size: 14.5*9.3*3cm. Material: plastic. Note There might be a bit color distortions due to different computer resolutions. There might be a slight errors due to different hand measurement. Package included: 1* compound string level.