Rope bridge blocks are used in conjunction with other rope bridge items. You can find this item in the Architecture section of inventory. A rope bridge block occupies one square block of space and has partial collision for players and weapons fire.
How to Obtain
This item doesn't generate naturally in any structure, so to obtain it you must either craft it or trade for it in a market world.
Added December 2013 in the 1.14.0 release.