Matt all 90's use approx 23cm long screw in bands or 52cm loop bands with screw on wishbones unless your talking custom bulk rubber or dyneema wishbones. Standard bands are 16mm or sometimes 18mm. 20mm are available but rather specialist. different manufacturers use different types of synthetic rubbers and some people prefer certain brands but the difference is small IMHO.
Dave.
Thanks dave, are the threads / screws all the same diameter? I have a feeling they are 22cm bands after finding a similar gun on the website, I guess thicker bands are more powerfull?