Fully considering the type of computer, the type of hard disk, the number of magnetic heads, the berthing area (inside landing) and other factors, the unique fixed hole, pin, socket and other personalized design can not only completely fix the head, but ?WelL Operated Synchronization?It has a welL operated synchronization and consistency of physical head separation. Hard Disk Head ComB This head comb is for builT in 3.5-inch hard drive. The Repair Tool Supports the HDD List -- 01) 104# For Seagate 7200.11 ST31500341AS 1500G - Four discs and eight heads; 02) For Seagate 7200.11 ST31000340AS 1000G - Four discs and eight heads. It has a welL operated synchronization and consistency of physical head separation.