The Schneider Electric GV2SN17 is a TeSys-range clear pilot light — a 17 mm diameter flat round lens indicator with a neon lamp rated for 110 V operational voltage. The clear lens gives a local signalling (clear light) indication, and the IP55 rating means it's sealed against dust jets and low-pressure water spray, so it holds up in panel environments where washdown or condensation is a factor but not full submersion.
The 17 mm diameter is the panel cutout size — standard for 16 mm to 22 mm indicator holes, but verify your panel's knockout matches exactly. The neon lamp at 110 V means it's designed for 110 VAC control circuits common in North American panels; don't use it on 24 VDC or 230 V without checking the lamp's voltage tolerance. The flat round lens sits flush, which reduces snag risk in a crowded enclosure.