My JP "wears" this assembly on the Tamiya TBU.
It goes on with magnets that engage the two screws in the top. It is made with thin sheet aluminium, magnets are glued with JB Weld. It has many coats of flat black.
Can't take credit for the design, I call it a "Strato Shield"
It puts the JP on a bit more even footing since you have to turn the whole tank to aim. We did it partly on the historical toughness of the JP's frontal armour and to encourage their use on the field.
I voluntarily do not use it in the "no cross the river" battles since it is pretty much unfairly invincible in that scenario.
"Luck favours the prepared!."