Stereo speaker size

The size is 61/2 but the fact.installed speakers have integrated tabs that secure them . When you remove the speakers the hole isn't designed t9 properly install an aftermarket driver. You can either purchase the adapters or in some cases ex. Alpine ,Pioneer ,JBL include an over sized mounting ring that should aid in installation. I recommend some sound deadening material such as dynamat or fat max to put on door because there isn't much inner door skin and tend to rattle with better speakers. GOOD LUCK