Arborist-specific: Kongfeets Figure 8 Descender with ears (or wings) to create a locking knot. The ears are designed to prevent the rope from slipping up to the top and forming a girth hitch which can strand the climber who is rappelling until they can remove their weight from the device. The large central opening allows you to overcome any knots on the ropes. Features & Specs: MPN: 80506R400KK Kong's Figure 8 Descender with ears (or wings) to create a locking knot. The ears are designed to prevent the rope from slipping up to the top and forming a girth hitch which can strand the climber who is rappelling until they can remove their weight from MBS: 40Kn Rope Size: 9 - 16 mm Aluminum Finish: Anodized, Hot forged Weight: 0.6 oz Color: Red