You will get the two air filters as pictured for your Amal concentric 900 series carbs.
These come with the threaded adapter for threaded 932 930 928 Amal, and hose clamp.
These will also fit the PWK alternative carbs in our ebay store.
They measure a total length of 3 1/2″, the mounting rubber flange is 5/8″ deep, and an ID of 1 7/8″.
These are nice quality with chrome cap and band.