ASSA ABLOY Fenestration: Experts in the OEM fenestration hardware industry ONE team. Every solution. Interlock USA and Caldwell Manufacturing Company are now ASSA ABLOY Fenestration. Our integrated companies will continue to provide the best hardware solutions for windows, doors and beyond. To do this, we will leverage the combined strength of the people behind two great brands. The Interlock and Caldwell brands remain integral to our company as product brands preserving their proud heritage. The Interlock brand, founded in New Zealand in 1961, will remain synonymous with innovative casement hardware, auto-locks and patio door hardware. The Caldwell brand, founded in Rochester, NY in 1888, will continue to set new standards for world-class window balances and commercial window hardware.