oh that one for specific bass only,coz diff bass got diff size of tuning hole,eg. fender and musicman got diff size of tuning hole for their neck,fender cant use musicman's detuner and vice versa,
for bridge,no need special bridge,any bridge that suit the bass will do =)
it works very simple,got sort of 'switch/toggle' attached to the detuner,when it is facing upwards,the tuning will be E,but when you pull it downwards,the note will drop to low D
vertical positon[E note] -> |
horizontal positon [low D] -> __
when it is horizontal,it basically loosen the string untill the note D
well you can adjust the note by noodling with the detuners [kinda hard to explain in sentence bro,you must see the detuner then you can get the idea]
and when you push the switch to vertical again,voila,back to E note,so no need to tune drop D,you can do it less than 3 secs by noodling with the switch/toggle
hope you're not confused after reading my explanation