The elusive VO2223A chip is always in great demand!
This is the chip that the DirkCheap SSR uses, as well as the MiniRen8VOXB controller, and the Renard Plus LCC8 and LCC16 controllers. This single chip replaces the need to have an MOC3023 chip and TRIAC on the board for A/C lighting control, but the tradeoff is that the VO2223A chip can only accommodate 1amp of current. So it's perfect for low-current situations where you're either using one or two strings of incandescent lights per channel, and it's a fantastic chip for strings of LEDs because they draw such little power!
You can search far and wide for a source of these chips, but DIGWDF located a supply of these and is passing the savings on to you. Minimum order is 4 chips.