What size hole does this primer mount in?
The mounting threads are 5/8", and the primer line threads are 1/8" NPT.
Is this ACS primer FAA approved for use in certificated aircraft?
No. This primer is not FAA Approved. It is intended for experimental aircraft use only.
Does the ACS primer come furnished with o-rings?
The unit comes with o-rings already installed. Replacement o-rings are available, p/n 05-19920.