Baer Heli Coil Tap - Wire Thread Insert - Bottoming Tap (STI) - Metric - M27 x 3Baer Heli Coil Tap Bottoming Tap (STI) for M27 x 3 Metric Threads When you need dependable thread repairs and reinforced engagement, this Baer Heli Coil Tap is your go to tool. Specifically designed for use with wire thread inserts (HeliCoil), it delivers clean, precise threads every time and is engineered to withstand the demands of professional repair work. The bottoming tap (STI) profile ensures threads extend fully to the bottom of blind holes,