Helvetica MH1.L1111.LB watch strap.
It is possible to fit this strap yourself, it is a little fiddly but relatively easy. Check out this video.
Helvetica MH.L1111.LB watch strap, 14mm Black leather with gold plated buckle.
Fits Helvetica 1 Light 26mm diameter.
Some watches come in different sizes, so please check the width of your strap and/or the diameter of your watch.
Having trouble finding your strap? More help is here.