Sorry, the S1 coupons already expired. I still have the 4 S2 coupons, plus I just got two more S2 that expire on 6/6.
On the bitmaintech.com web site they no longer list an s2 for sale but rather a "kit" whereby you put the components in your own case and attach you own PSU.
Do you know if the s2 coupon would still apply to this SKU?