Safety Technology International， Inc. STI-34601 Additional Wireless Doorbell Button， 8-Channel Receiver or 4-Channel Talking Voice Receiver (Speaks 53 Words， English or Spanish) Required， Sold Separately<div style="text-align: left;"><strong>[Product Information]</strong><ul><li id="replacementPartsFitmentBullet" class="aok-hidden" data-doesntfitmessage="We're not sure this item fits your " data-fitsmessage="This fits your "><span class="a-list-item"><span id="replacementPartsFitmentBulletInner"><a href="#" class="a-link-normal hsx-rpp-fitment-focus">Enter your model number</a>to make sure this fits.</span></span></li><li><span class="a-list-item"> Additional doorbell button for STI wireless chimes Series， requires receiver sold separately </span></li><li><span class="a-list-item"> Easy to install no expensive through-the-wall drilling </span></li><li><span class="a-list-item"> Water/weather resistant for outdoor use </span></li><li><span class="a-list-item"> Operates up to 500' (line of sight) </span></li><li><span class="a-list-item"> Limited one year warranty </span></li></ul></div><img src="http://ecx.images-amazon.com/images/I/21wCx%2Bhf-6L.jpg" noproxy>