I wish to develop a comprehensive design for a non- electrical self-retracting line device. It needs to be able to hold approx. 80ft of rope that has a 4mm circumference. It must feature UV resistant plastic casing with quality internal components. Dimensions are negotiable but should be no larger than around 345mm x 245mm x 100mm and weigh no more than roughly 8kg. Must also have the ability to slot into a purposefully built bracket system for mounting purposes.