For your log splitter, it is recommended to use Hydraulic Oil AW-32. AW-32 is a common type of hydraulic oil with specific properties suitable for various hydraulic systems, including log splitters.
When adding hydraulic oil to your log splitter, follow the manufacturer's instructions regarding the proper oil fill level and any recommended maintenance procedures. These can be found in your operator's manual which should have come with the product. If not you should be able to find a download on the product page on our website.