The MGT30 Miniature Glass Tube Variable Area Flow Meters are equipped with a needle valve in the base to facilitate the precise setting of gas and liquid flow rates. On request, these valves can also be fitted in the top connection block. The mounts are made of stainless steel and feature a specially designed fitting for the glass cone. This device permits easy cone replacement without removing the mount. The top connection block of the MGT30 features a non-return valve to prevent backflow of the product (exception: flowmeters with a valve in the top connection block).