Each skylight has two identification numbers. One number is on the metal spacer between the two panes of glass after the word VELTERM. This VELTERM number is the glass identification number.
The other number can be found on a data plate attached to the wood of your unit. The location of this data plate depends on your product model and when it was manufactured. You can visit our Self Help section here to determine exactly where to look for the tag number on your model.