The S variant of the HW 100 is the one with a Sporter stock, this stock is made from finest walnut and then oiles. It has checkering on the fore end and pistol grip and a nice sharp comb on the stock. The S also has a full length barrel and this gives the HW100s a great shot count. The HW100 is probably the finest all round PCP (Pre-Charged Pneumatic) on the market today. It is the darling of the target shooting world with multiple national level shooters using them.