my dad has a double glass and mine is a single i think...they both have the same sound to me....i love the sound of glass...nice and soft sounding...ive seen turkeys not respond to anything than dad hits his glass does a few soft purrs and some clucks or some soft yelps and bam there on there way...it has a totally diffrent sound from any other call...always nice to have...but i always carry tons of strikers like others said...