Helvetica MH1.L2211.LG 18mm watch strap.
It is possible to fit this strap yourself, it is a little fiddly but relatively easy. Check out this video.
Having trouble finding your strap? More help is here
Helvetica MH1.L1111.LG 18mm watch strap.
Please check the width of your strap and the diameter of your watch.
18mm Apricot-sand leather strap with stitching.
Helvetica No 1 light 18mm diameter.