Senco nailer question

[David Todtman]

I bought senco framing (stick) nailer in a yard sale. It is little used and works fine with 3" nails. It has a sticker that reads, "Block out recommended for 1 7/8 - 2 1/4 nails". What is block out?

Thanks in advance. David Todtman

[Nova]

It's an optional nail guide that clips into the rail assembly when using shorter nails. See:

[David Todtman]

Thanks Nova.