I used a Black&Decker "Blockbuster" 3/8" with: variable speed, reversing, and jackhammer drilling action No. 7197. I was bought about 5 years ago and has Made in England on it. It worked fine for drilling 1/2" anchor bolt holes in my concrete drive way. It is also not much bigger than a regular 3/8" drill and is the one that I use most ofter for my odd jobs around the house.
Of course you cannot go wrong by buying a higher quality one like the Bosch.

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84 300D, 82 Volvo 244Gl Diesel