These two goods are with similar shape. Many clients are easy to make a mistake. Here I will tell you how to distinguish them.

First, the head diameter of them are different. The LUA7316 Series is with head diameter of 24 mm, but the LUA7317 Series is only 18 mm.

Second, the LUA7316 Series has different lens for you to choose from. The LUA7317 Series only has 1 lens of 30 degree.