bolt-on
Of an accessory: capable of being bolted on or otherwise attachedOf an accessory: capable of being bolted on or otherwise attached.
UK/bəʊlt ˈɒn/US/ˌbolt ˈɔn/
Meaning
2 senses(not comparable)Of an accessory: capable of being bolted on or otherwise attached.
(figuratively, not comparable)Used to extend an existing system, operating as an add-on or plug-in.