Chalk Line was specifically developed for the punishment gyms inflict on rope Whether you have a small gym or big wall, the Chalk Line can take the constant falls and belays. The Str8 Jacket construction allows the Chalk Line to hold its shape and keeps the cover and core in balance which virtually eliminates sheath slippage. This will reduce flat spots and help maintain the performance of the overall rope. The Chalk Line will provide a safe and easy belay through a variety of devices while still maintaining its shape. Gym owners who use Chalk Line love their longevity which saves them money by not having to replace them as often. Endura STD-DRY water-repellent coating applied to the core of all Chalk Line models.