WS2811 DC24v 4X5 leds rigid matrix

This product is customized by one of our USA customers who use ws2811 ic and 5v, 12v product
usually.  in order to reduce voltage drop, the customer would like to use DC24v, so we use 2pcs
ws2811 ic to achieve that, but it just have 1 pixel

the matrix size : 90x105mm, 
LED spacing : 75x60mm (the pixel pitch is 15mm)
led amount : 4x5=20pcs
cables: 3pin waterproof connectors with 35cm wire length