It can mix 1 full bag (50 kg) of cement per batch, combined with the required sand, gravel, and water. The 400L drum concrete mixer is a heavy-duty, towable site mixer featuring a wide 400 mm to 450 mm drum opening and powered by a 3 kW to 4 kW electric motor (or 6 to 8 HP engine), designed to quickly blend and discharge 220L to 280L of wet concrete per batch.