The Apex Bone Collector Sight includes a lightweight/compact design that allows sight to match industry trends for smaller bows. Also new on the Bone Collector is the Tru-Flo fiber design. Extra, extra long fibers are routed through the bracket for increased durability and exposure to UV light. The new pin design allows for quick and easy fiber replacement. The special light location allows for more effective light distribution to fibers. The Aperture has a 1.8ö inner diameter.