Taramps Automotive Digital Voltmeter And Sequencer Vts 5.1 Blue Led, Black Product Features All functions are accessed by pressing the FCN key, sequentially. The activation of mixers and/or audio processors should preferably be done at the S1 output for a correct sequential activation (when switching on, from S1 to S5 and when switching off, from S5 to S1), thus avoiding unwanted transients when switching on the amplifier (popularly known as "pop"). IMPORTANT: Outputs S1 to S5 are intended only for activating (REMOTE input) of the sound equipment. Voltage Check: With the VTS 5.1 without the remote signal it is possible to check the voltage of the batteries, press FCN and the voltage will be displayed and whenever you want to turn off the display press FCN again. Function SPL:Press FCN for about 10 seconds until ?SPL? and ?On? appear. This function increases the overvoltage protection (default = 16.5V) to about 19.5V. To deactivate this function, press FCN again for 10 seconds, until ?SPL?and ?OFF?appear on the display. Shipping: Shipping is complimentary within the lower 48 US States. We Do Not Ship to PO/APO Boxes, HI or Alaska We Do Not Ship Outside of the Continental US All items ship within 24-72 hours of Payment For large items that require Freight shipping a valid phone number is required to call and schedule your delivery Terms of Sale and Feedback: Feedback is extremely important to us and If you are satisfied with our transaction, please take a moment to leave Positive Feedback. YOUR Satisfaction is our #1 Priority! If there are any issues, PLEASE contact us BEFORE leaving a neutral or negative rating so that we may resolve any concerns. We PROMISE we can make you happy if you give us a fair chance. Returns / Concerns: All items qualify for returns within 14 - 30 days of receipt. Buyer is responsible for return shipping on any item that is not damaged Please be sure this is an item you want before making your purchase. Customer Satisfaction is our TOP priority! All items are IN STOCK at time of listing. Inventory changes constantly and it is impossible to maintain a perfectly accurate count of all items. Please do not penalize us if we have to issue you a refund! Thank You For Your Business!