What Tax Rate to mention on Eway bill for giving construction Material on Rental ??

We provide construction material on Rental basis to various clients. the material is on returnable basis.

While preparing Ewaybill at the time of Dispatch/Receipt of material what should we mention in Tax rate column

Should we mention Zero or should we mention tax rate under which our goods fall i.e (9+9)

We are confused because this is not a Sale, this is only dispatch and receipt of rental material.