This is a standard male Funnel Bowl from Grav Labs. It's made using high quality borosilicate glass and will fit any 14mm or 19mm opening.
We like the way Grav makes their bowls. They call this a "Maria" style handle - you can see that the ring goes all the way around the bowl, making it easy to use.
The 14mm bowl is pretty standard for most bongs. This is the most common sized bowl used.
The 19mm bowl is usually found on the biggest of bongs. If you have a big, thick, heavy piece... this is probably your bowl size.