Where to find machine heads

[Quickfinga]

My ibanez has gone through two machine heads in the past year and I cannot find anywhere that sells single machine heads. I'm looking for this model: 2MH1WB223S or something like it

[mmbongo]

A pic would help find a suitable replacement.

[Nev375]

Planet Bass Online Store: Gotoh GB7 Tuning Key-Chrome

Out of curiosity, how exactly are your tuners failing?

[Quickfinga]

http://cachepe.samedaymusic.com/medi...80c47edf19.jpg

Thats the bass

Also the screw part where the string is actually inserted strips out