This Insert slips into the Manticore shaft Yoke where the coil is mounted to support the Yoke ears from braking & reduce any flexing that may occur when swinging. The new design of the Manticores coil & shaft is a welcomed improvement for those who have had to replace or repair the expensive coils after a yoke ear broke off the coil.(old design) With the new design it will be cheaper if this happens now as the yoke ears are on the shaft instead of the coil. Thanks Minelab! Unfortunately this is bound to happen to some of us out in the field causing down time, Missed treasure & Money so I designed this Yoke Stiffener to help mitigate ear breakage on the Manticore. It fits nicely into the end of the shaft and braces the ears and washers for best performance. It is light weight at about 9 grams & has a drain hole for water in the shaft to escape & is printed with 100% infill = water tight for divers like me.  Made from ASA plastic (Acrylonitrile styrene acrylate) not pla. (Polylactic acid) PLA has a very low melt / deformation temperature. ASA has a higher melt / deformation temperature, High impact resistance, Strong UV & Chemical resistance, Water Resistant with Anti-Static Properties, its Tough and Durable with a low-gloss finish. Better suited for this application.