Darn, can't remember the place ordered from!
do a search for "mil-spec elastic fabric" or something along the lines of including 'military' in the search query. They're colored in the OD, Tan, int'l orange, and a few different camo patterns.... and definately better than the elastic you'll get on any of the headlamps these days.
another option (albeit expensive).. is to look fo flat bungee cords in the longer lengths. These are incredibly durable and strong, have all the popular hated color combinations (yeah, color combos that would make pippi longstockings socks laugh), and can be had with 1/8 thichkness at the smallest size.
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There's also an elastic webbing material made with lycra... that's nother option if you aren't into the 'over-bulkiness' of the mil-spec and bungee headthrobbing squeeze
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Hope this helps