this item does not come with a manual but if you want to have a look for more detail 
it's here ~ https://uk.yamaha.com/files/download/other_assets/9/314339/xp120sd_en_om_c0.pdf 

has some dings and scratches (see photo's) due to age of the pad, but tested and working (all three zones) 
works with most modern Drum modules. 

Information 
After making acoustic drums for more than 40 years and acquiring deep and highly detailed knowledge of drums in the process, Yamaha has developed the DTX-PAD, a 12-inch electronic snare drum pad with a transcendent feel. The drum head is made of TCS (textured cellular silicone). By adjusting the sizes and concentrations of the tiny bubbles in the TCS, we have created two different types of pads, a snare pad and tom pad, that both feel perfect. When we were developing this pad, we had it evaluated repeatedly by the world's top drummers. The detailed sense of perfection of these drummers is reflected in this drum pad. As a result, this drum pad performs superbly, like an acoustic drum, and it feels so supremely good that professional drummers brim with pleasure when they first start playing it. 

At the same time, it is fantastically quiet. Its excellent feel and quietness make it ideal for home use. The pad is divided into three zones and supports open rimshots and closed rimshots. 

In addition, you can assign different voices to different zones. This makes highly original performances possible. For example, you can create an acoustic drum sound when you hit the head area, a cowbell sound when you hit the open rim area, and a loop sound when you hit the closed rim area. 

Also, the pad has a pad controller (the black dial on the edge) that you can use to readily control the snare wire tuning and adjust effects.