With Sq.Are D Qo And Homeline 150 Or 200A Breaker Box, 3/8" Space On Main Product Details ?UL Tested?Our generator interlock kit has already passed the UL test and got the test report, the manual transfer switch device allow portable generator safe back feeding power supply to distribution panel and home line. Prevent utility and generator supplies from being ON at the same time. Aren't putting electrician in dangerous and damage electric devices during power outages ?Compatible Models?CZNZN electrical interlock Kit compatible with Square D QO or Homeline 150 or 200 amp load center breaker panel box. Apply to 1-3/8 inches interval spacing between main and generator branch breaker, other same space panels may fit. Fit indoor/outdoor generator. Mounts on front of breaker panel, no need extra control box or wiring. ?Great Tool for Conversion Power?Generator lockout kit "Lock position" by sliding the lock plate up and down, easy to switch power supply from utility or connect with a generator to power up all of your home electrical appliances, clearly indicating what you are running when protecting your generator. Stay away from darkness and coldness when power off. ?High Quality and Reusable?Built-in high quality chemical resistant and thickness solid aluminum alloy Interlock switch plates, Very durable for long term use. After chamfering and surface oxidation treatment, generator interlock kit will keep fashion look and smooth surface protect user hand. ?Items Included Warranty?Recommend to operate by licensed electricians. Easy to install, Package including everything you need. 2 Interlock plate, 3 Step screws and nuts, 1 Drill Bit, 1 Generator Start-Up Procedure Label, 5 Remind Label, 2 Zip Ties, 1 Installation instruction. Free risk on lifetime warranty. Pls contact us if you need any help. Payment We accept PayPal and credit cards via PayPal. Taxes - US We collect sales tax, as required by law. Shipping We make every effort of shipping within 3 business day of payment clearing. The estimated delivery time is 2 - 5 business days from the shipping date. Policies If you do need to return your item, please contact us via email (you will receive an email when your product ships with additional details - Subject: Important information about your purchase). You will then be provided with a return shipping label and packing slip. Pack the item carefully. Include the packing slip, apply the shipping label, and return the item within 30 business days of the date you request a return, or your return will be canceled. Once we receive your order we will inspect the return. Please allow up to 5 business days of receiving the returned item for your refund.