LED high voltage strip is strips with AC110V or AC220V input voltage; And strip with DC12V or DC24 input voltage will be regarded as low voltage strip.
Beside the difference of voltage, the appearance and applied place are also different for high/low voltage strip. You can see appearance by following picture:
Main materials of high voltage strip are PCB and clear PVC Tube. There are two alloy wire on two side of strip and the LED are on the middle of strip. Super quality high voltage strip is always with good transparency PVC tue, no impurity. On the opposite, bad quality ones are with yellow color PVC Tube and some impurities. The main characteristic of high voltage strip is that they can connect 50M or 100M together, while low voltage strip can only connect 5-10meter together. Yet, safety performance of high voltage strip is lower. Here you can find picture of high and low level high voltage strip for your reference.
Low voltage strip is totally different by appearance, no two alloy wires. It's becasue circuit of low voltage strip can be made on PCB. The main characteristic of it is its high safety performance. But they can only make 5Meter/PCS and the longest connection is around 10meter. Of courst, you can make it longer by connect them in parallel. There are non-waterproof(IP20 or IP33), IP65 waterproof(Glue or Tube) and IP8 waterproof( silicone tube with injection Glue) for low voltage stirp.
I'm sure you make know the difference between them by learning above technical data.