Four towers that attach to vehicles with raingutters or, with brackets, to caps and camper shells. Yakima has made millions of these things; it's a great design that looks sharp and is tough as nails; fits virtually any vehicle with a raingutter or driprail; tough Zytel nylon won't mar vehicle finish, absorbs road shock and won't tweak your raingutters; pivots to line up with raingutters that are out of parallel; 4 to a set; lockable with SKS cores.