Ah, sorry. I directly compared the parameters of the LSW1599-4M to the product catalog on Lishuis website. Didn't suspect that Lishui did custom ordersWhere did you get the information, that the LSW1599-4M is a LD-SS03? The ones from Yose power are square wave for sure.

Thank you for the heads up. I alsmot wasted 60€.
Do you happen to know any place to buy the sinewave variant?