Quoted FOB USD30/per unit is for style 1352 single ring diameter 80cm, single light emitting color in warm or warm-white or white; FOB USD37/per unit is for style 1352 free control light emitting colors among warm, warm-white and white.  Avaliable regular ring diameters are 20cm, 30cm, 40cm, 50cm, 60cm, 80cm, 90cm, 100cm, 120cm to be assembled for sing ring, double rings, three rings ...... and so on.  Style 1352 can be customized into your requested specifications, too.