As an amp tech for several decades, I cant tell you how many broken and bent tubes and damaged sockets I’ve seen in Blues and Pro Jrs. The new III version comes with a cage but it is not available as an accessory. So, at the request of a regular customer, I made a couple of protective tube cages and then decided to make them available to everyone.
They are available to purchase on Reverb.com or if you are in the Chicago area, you could buy direct from me at Chicago Fret Works/Amp Works, 4229 N. Lincoln Ave, Chicago IL 60618 773-698-6246
https://reverb.com/item/11938366-tube-cage-for-fender-blues-jr SOLD OUT!
https://reverb.com/item/11953199-tube-cage-for-fender-pro-jr
Pro Jr $20 Blues Jr $22