Competition Electronics ProChrono DLX Chronograph Onboard Bluetooth connectivity, and more options with FREE apps for iOS, Android, Kindle, PC, and Mac Internal and external refinements with updates to the circuitry and enclosure design Built-in full featured operating system with multiple shot string memory and statistics Memory Capacity: Up to 9 strings of up to 99 shots each Faster internal shot clock for improved accuracy to +/- .5% or better Minimum Time Between Shots: 500 mSec Made in the USA quality at an affordable price 2 year warranty against defects in material and workmanship, and a 1/2 price repair guarantee Over 30 years of experience in chronograph design and manufacturing Replaceable Alkaline 9 volt battery power (not included) for 20+ hours of operation Bluetooth: BT2 and BT4LE Temperature Range: 20-100 degrees Fahrenheit Velocity Range: 20 - 9,999 feet per second Weight 2.1 lbs Size: 16x4x3-1/4 inches Please Note: This device is meant to be used outdoors with good lighting conditions to register properly. For use indoors it is recommended to use the Competition Electronics Indoor Lighting System, sold separately.