This transformer allows for continuous wall operation or for recharging re-chargeable 9V batteries in any of your OWL fiber test equipment that has a charger port

The WS-9V-2.1 has 2.1mm connector for for use with WaveTester optical power meters.

NOTE: using this transformer while non-rechargeable batteries are in the unit may produce an unsafe condition, and may cause harm to the equipment or the user.