Ravin Crossbows recommends that strings and cables be replaced at your local pro shop or the Ravin Service Department. If you do choose to replace strings and cables yourself, use only this Ravin String & Cable Set and the Ravin Press. These strings and cables are compatible with the Ravin R9, R10, R15, R20 and R29 crossbows. Ravin Crossbows Ravin R9/R10/R15/R20/R29 String & Cable Set R190