Ofna and Hudy have the 1/4" drive bits. I have the Ofna ones in both metric and us and they work great. The ends of the bits are very strong and perfect for a hand held screw gun. Anything from Hudy is good. I have the hex wrenches and they are by far the best ones I have had to date. I have owned Ofna, Losi, Thunder Tiger, EDS and all are pretty good however the Hudy ones IMO are the best quality.