This Chimney is NOT for the Model 23 Lamps currently being sold, for these new lamps you will need the R910-2 Chimmey. It is confusing because there is a model 23 (which uses the R103 lox-on) and a model 23a (which uses the R910-2 heelless)
This is for the older Aladdin Oil Lamps. The Lamps being sold at this time use the R910-2 Heelless (slip on) Chimney.
Customers in High Altitude areas (4000' and over) you will need a high altitude chimney for your lamp to burn at its brightest, item R905 and a adaptor (item # to change your lamp from lox-on to heeless since there are no longer any lox-on high altitude chimneys. ... OR ... Another option is to add a Light Booster (brass or nickel) N108b brass OR N108n nickel to the top of your chimney. Look for these items in the search or contact us for personal assistance. sonset@centurytel.net