Arma Drillo transmitter housings and drillheads from Armadrillco are vibration-proof, protecting electronics from excessive shock and heat. They are easy to assemble and disassemble on command. Lock pins cannot be over-torqued or broken. Three styles of bits will fit and work on the drillheads, including bullet-tooth, flat-blade or roller-cone bits. The bullet-tooth bit has adjustable teeth, and teeth supported on heads instead of necks. They have stainless steel key components, and numerous bit designs are available. 800/994-0915; www.armadrillco.com