This is a reproduction of one of Seiko's rarest straps, which was originally available only in 19mm for their 6105 diver. It is thick and durable (though v.1 is a little stiff). It measures approximately 130mm for the long end and 80mm for the short (not including buckle). It is the same thickness all the way down without taper. Comes with a pair of 2.5mm "fat boy" spring bars. Available in 3 sizes (19mm/20mm/22mm).
The version 1 needs some breaking in but should be good to go if you utilize the Hot Water Trick, or keep it strapped on a pillow in your watch box for a while.