I purchased these for my KST BLS915 and they have been working great. I couldn't get out one of the old gears, so I found a video on youtube that gave me the confidence to get back at it.
M
Marco C.
Why buy a whole new servo?
My servos started having some play. I replaced the gears with these and now the servos are as good as new. Takes 10-15 minutes to change the gears so it is totally worth it.