The JFCV-1000 is an electronic whistle, designed specifically for use in WFTDA-based roller derby. The main unit is strapped to the top of your hand (I recommend the hand that you point at skaters with when issuing a penalty) while the controller hooks onto your middle finger, leaving your index finger free to point at skaters and your thumb to operate the buttons.

At a click of single button you can:

• Issue a penalty (i.e. tweet)
• Declare lead
• Call off a jam
• Perform a rolling whistle

To provide greater accommodations to Hard of Hearing (HoH) skaters, the JFCV-1000 also has a series of LEDs which light up when the unit is whistling, allowing HoH skaters to "see" the whistle being blown. Combined with pointing at the skater being penalised, this maximises the ability for skaters to notice they are being penalised and leave the track.

The LEDs can also be turned off to facilitate sensory accommodations.

A guide to changing the settings is available both in the datasheet PDF as well as the youtube video at https://youtu.be/_NEYYgX_yTY.

For instructions on how to put it on, see the datasheet or the youtube video at https://youtu.be/MYWlALlKWhs