GROP-ON timerbox has relays for 3 of 4 sockets (sockets 1, 2 & 3).
Relay is 40A Solid State Relay (SSR) with max volts 440V (AC).
With 40A relay it's possible to handle heavy loads like up to 1200W HPS light.
Totally max output is 16A / 3650W @ 220V (AC) what we can provide for timerbox output power rate.
It's totally silent and uses less than 40mA power, it's like 100x better than mechanic relay or contactor.
Why it's better? Well, good question! It's newest technology, it doesn't have moving parts like mechanic relays has.
And why we're using 40A, you might think it's over rated for 16A usage. Actually it's just fine, little over rating makes it stable and last longer. Also it has best price quality ratio. If you would like to use 10-30A relay - you could save like one dollar and pay later 20 dollars for new relay, because you smelted under rated relay.
Solid State Relays is used in 3D-printers, CNC-machines, Laser cutters and so on..