This product is a re-fabricated neck-seal designed to fit the following models of Sparklets soda syphons:  Original glass straws, as supplied or found on Sparklets Type C, D and "Prana" soda syphons - and their close varients (as pictured).  The outer diameter of the neck seal is 30mm and its thickness is 6mm; the central hole is approximately 8mm in diameter and is intended to be a tight fit on the original tubes.  CAUTION: Tubes of over 9mm diameter may require slight enlargement of the central hole or heating of the seal to soften it prior to insertion of your tube.  In general, we recommend that the seals be soaked in hot water prior to use and inserted over the end of your tube whilst still warm, before allowing to cool in place.
 
Care needs to be taken when inserting the old glass tube into the centre of the seal as old glass can be brittle and fracture easily.  It is recommended that stout gloves are worn when doing this and the end of the glass tube is lubricated with water soluble lubricant such as cooking glycerine or even just water.  
 
The seal is fabricated from a food-safe grade of synthetic rubber - hence the blue colour (Either approved for food contact use by one, or more, of the UK Water Research Association, US FDA or EU materials safety schemes).
 
Price includes UK postage; non-UK buyers will need to inquire about postage costs to your country. 
Contact us by e-mail to purchase (PayPal, BACS, IBAN and WISE all accepted)
 
[This product may also fit other brands of soda syphons such as those made in France, Germany, Czechoslovakia and Hungary in the period from 1920 onwards]