It's a thin gel-like consistency that is nude in colour and feels weightless on the lid. It is very similar to the UD but I personally feel like I get better results from theBalm's offering. My eyeshadow never creases with this stuff, not even after a very long work day. At full price the UD Primer Potion is £15 for 11ml, whereas at full price theBalm Put a Lid On It is £14.50 for 11.8ml so it is slightly better value too.
If you are in the market for a new eyeshadow primer I would definitely recommend looking at this as an alternative to Urban Decay or Too Faced! It is available from FeelUnique.com for £14.50 with free worldwide shipping.
Hope you all have a good day!