The Spacer (OEM Part No. 3128310520) is a structural spare component compatible with Simba M4C, Simba M40S, M4C, Simba H1354, and SIMBA H1254 underground drilling rigs. Manufactured from durable alloy steel, it is designed for the rock drill assembly rotation unit position. The spacer provides accurate component spacing and alignment within the assembly, helping maintain proper mechanical positioning and stable operation. Its strong construction ensures precise fitting, reliable support, and long service life under heavy-duty underground mining conditions. This OEM replacement spacer helps maintain equipment accuracy and operational stability.