Instrument Head
Handle Connection Systems and Compatibility

HEINE 3.5V full size instruments and handles
are available in 2 connecting systems:

All full size (3.5V) Heine instruments and power sources feature our patented "AV" automatic connector for increased durability and a positive lock between handle and instrument. Due to standardization issues, all full size Heine instruments and power sources are also available with the traditional bayonet "twist" style connectors ("TL" connector) popular throughout North America.
AV connector: HEINE's exclusive patented automatic connecting system. Positive locking mechanism ensures a secure connection between Instrument and handle.
TL (Twist Lock) connector: Welch Allyn 3.5V style connecting system. All HEINE TL Instruments and Handles are compatible with Welch Allyn products.
The simplest way to distinguish between AV and TL Instruments is to remove the Instrument from the handle and stand it up on a flat surface. TL products will stand up and AV product will not (see images above).