First of all, I am very satisfied with the product. There is no delay at all when used in Bluetooth mode, and when reconnected in sleep mode, it is recognized quickly without delay. The sound isn't too loud, so the typing experience is nice. Personally, I can barely feel the resonance sound. However, delivery is too slow. I purchased it on December 19, 2023 and received it on January 9, 2024, but I am very satisfied with the seller's response. If you purchase it leisurely, it is a product with the best value for money and you will not regret it.