I am also selling on sites other than Mercari and my own website, so please refrain from immediate purchase and confirm availability via comments. Sound Japan 3.8 tatami mats, -35db, is for sale. This is originally a double-walled soundproof room. It had a performance of -55db at 500Hz, but due to the following reasons, it is being sold as a single-walled room. ・The double-walled structure weighs around 2500kg, which is too heavy for installation in a typical home. ・Even a single-walled structure provides sufficient soundproofing performance of -35db. This is the inner soundproof room, and the exterior is not finished, consisting of an aluminum frame + carpet backing (black), but it can be used as is without any problems. * Previously, the Power Double soundproof room guaranteed a performance of -40db even in a single-walled configuration, but the current product specifications have changed, with concrete removed from the wall materials and replaced with a composite of wood and resin. The door specifications remain the same, with a heavy glass door, but the wall weight has been significantly reduced, so this time it is set with a -35db guarantee. * New LED lighting and tile carpet (you can choose the color) are included free of charge. * Two outlets are provided in one location, and a two-outlet switch (for lighting and ventilation fan independently) is included. **Size** Inner dimensions: 2,124 x 2,821 x 1,890mm (width x depth x height) (ventilation fan + approx. 100mm) Outer dimensions: 2,218 x 2,915 x 2,080mm (width x depth x height) **Soundproofing Performance/Weight** -35db, approx. 1100kg **Delivery and Installation** ・In addition to the main unit price, a basic installation fee of 138,000 yen (tax included) will be charged separately. (Additional charges may apply depending on the region) **Notes** ・The weight is approximately 1100kg (the door alone weighs 60kg). ・Realistic installation is possible in reinforced concrete buildings (upper floors possible) or on the first floor of a wooden detached house; in the case of old wooden buildings, reinforcement of the subfloor may be necessary. We recommend obtaining prior permission for rentals. **Condition** ・This soundproof room was ordered by a customer, but due to circumstances, installation was not possible after delivery, so it is in a packaged state. For an accurate installation cost estimate and to purchase, Please search for (株)Tokyo Sound Box and access their website.