The present invention provides a repair resin composition for repairing breaks in a vehicle windscreen and curing units for curing the repair resin after it has been inserted into the break. The present invention also provides a method of repairing a vehicle windscreen, comprising inserting a resin into a repair zone, wherein the resin comprises a photoinitiator that activates when exposed to light of an activation wavelength, wherein the activation wavelength is between 370 nm and 425 nm, and curing the resin by emitting light including light within the activation wavelength range onto the repair zone.