Opening is 5-3/8" diameter 185-4989 ONAN AIR HOUSING Kubota 12723-3885 NOS Winner pays $9.95 shipping and handling anywhere in USA. Other countries must contact me for a postage quote. Please look at my other items in my STORE and add me to your favorites list. NOS means new old stock. These are items that are still in new and unused condition that have been on the shelf or in storage for a number of years. Most of my items are in the original factory boxes or cases. Some of these boxes show a good bit of wear and tear from storage time and handling. I try to add to my store listings all the time. Please keep in touch. I am not an expert concerning much of what I sell but I do have a certain amount of "resourcefulness". Please send part numbers when inquiring about certain parts. Sincerely, Mike Click Here. Double your traffic. Try Vendio Gallery Risk FREE! On Mar-08-08 at 17:27:29 PST, seller added the following information: ... Powered by Turbo Lister The free listing tool. List your items fast and easy and manage your active items. 11-3-21