... 1, Product Information: Product Name: amplifier backpack with built in speakersFabric: 600DSize: 45*33*21cm, also to be ... Silk Screen Printing ; Emboidary ; Rubber patch, etc...Parameters:Speaker diameter:57mmAUX input impedance:10-20KΩ output impedance:4ΩFrequency ... etc.3, Products & Material Standards:We can produce bags in with material meet Environmental Standards (PHTHALATES FREE, AZO FREE, ...