The 13mm Bosch is the most common professional drill in Nigeria — 13mm means the chuck size, so it can hold up to 13mm drill bits.
Two models you will see everywhere:
Model Power Speed Weight Best For Price in Nigeria
**GSB 570 Professional** 570W 0-3000 rpm, 48,000 bpm impact 1.7 kg Home, light concrete, wood, steel ~₦54,700
**GSB 13 RE Professional** 650W 0-2800 rpm, impact 1.8 kg Site work, full hammer + rotation