SMD for Proto Board

I have the Arduino Protoboard and want to add some leds to the smd sector. Problem is I don't have nor understand the size I need. Specs say the smd sector has a 50 mils pitch. I am wanting to use all 7 smd slots for leds. Any idea what size smd led I need?

Assuming you are using the ProtoBoard pictures here: metachronistic the prototyping are is for a 14-pin SOIC surface-mount chip, not for individual surface-mount components.

Looks similar. I am using this one...Proto Shield Rev3 (Uno Size) — Arduino Official Store
Hoping to use the SMD sector to illuminate leds to indicate signal. Perfect use for the sector. If not, the sector is worthless to me.