I dont think there is any difference.
My m8 bought one like the 1st one and its just a heat mat for 15 and i bought the second one off ebay for 15 aswell. They are just heatmats but the second one is just specialised for lizards i think
The second mat is for glass as you can stick it to the bottom of the outside & then you get 4 little feet that you stick to the tank in each corner to give the mat space for air flow. You can get them cheaper than that (about 1/2 price) from '888 reptiles'.
The first mat is the standard 'all purpose' type & very common.
yeah you get 4 rubber feet that stick to the bottom of the glass tank in each corner. the heat mat also sticks to the bottom of the outside of the glass tank.