Here is something that may interest you.
Many years ago my dad was a field repair techy, and covered all sorts of consumer electronics. Back then the level of training and education was seriously impressive in comparison to most of today's technicians. Much more worthy of the title Engineer. Anyway, here are a couple of delay lines he extracted from old valve / transistor era TVs.
It seems that these were Mark 2 delay lines. The Mark 1s were even bigger! The one on the left measures 90mm long, by 42 wide and 6.5mm high. The one on the right is considerably thicker at 10mm, but 39mm wide and 80mm long. Originally they would have been in plastic housings. Both are pretty weighty lumps of glass.
The reason for one being 10mm shorter than the other, and also the reason for their being out of their original plastic cases, is just visible in the centre. One of my dad's hobbies is gem cutting! Old delay lines provided a good source of high quality material to practise a variety of gem cuts. The photo really doesn't do it justice, it really sparkles and glitters.
You can just about see the moulded ripples in the side, and the moulded-in feet underneath. The piezoelectric transducers are clearly visible.