g' by Free Fall Apparatus by LascellsUse in conjunction with an accurate millisecond timer to calculate acceleration due to gravity. The timer starts when the ball bearing is released from the release unit the base has an integral vibration sensor which stops the clock as the ball bearing hits the impact plate. Replace the ball bearing reset the timer and the unit is ready to go again. When used with Lascells timers or other models with de-bounced inputs no additional power is required. If the timer used is found to have “bouncy” inputs then a 4 second delay can be added to the impact plate outputs by powering the unit with 9V DC.Please note this G By Freefall Apparatus is not compatible with the Philip Harris S-Range Scaler Timer due to the arrangement of the start/stop switches.Works with the Lascells Millisecond Timer (sold separately)