The dimension of the spring unit for sofa is customized.

And the common specifications of the single spring used for this spring unit are as below:

Wire Dia.	Top Dia.	Waist Dia.	Border Wire	Height	Turns
mm	cm	cm	mm	cm
1.8-2.4	6.5-9	4.5-5.5	4.8-5.0	6-23	4-8