FS65 Series Standard Duty Balanced Pressure Swivel Joint, 3/8-18 Female Pipe Casing Thread To 3/8-18 Female Pipe Sleeve Thread

For FS65008-0606-01, both ends are 3/8-18 NPTF female. One side is the female pipe casing thread and the other is the female pipe sleeve thread, so it is built for a 3/8-18 female to 3/8-18 female connection.

This FS65 series swivel joint is designed for industrial hydraulic applications, so standard hydraulic fluid should work just fine. The product documents also include a fluid compatibility guide, so you can double-check specific fluids there.

Buna-N is the default, which is what the -01 suffix on this part number indicates. If your application calls for something different, there are two other seal options available across the FS65 series: EPR (suffix -04) and Viton (suffix -06). The part you're looking at here is spec'd with Buna-N out of the box, so if that works for your fluid and temperature range, you're good to go as-is.