The Ermeto DIN tube to tube hydraulic tube fittings from Parker are leak free and can work under high pressures.
PARKER Bulkhead Union SV from PARKER HANNIFIN
Tube Fittings Division - Parker
SV12LCF Parker, Parker Hydraulic Bulkhead Compression Tube Fitting M18 x 1.5 Made From Chromium Free Zinc Plated Steel, 110-589
M10MBC1/2N-S - A-LOK Metric Tube NPT Male Bulkhead Connector - MBC
Hydraulic Fittings, Hydraulic Adapter
Bulkhead / Compression Fittings / Connectors / Hydraulic - Flowtech
Crimped Thermoplastic Hydraulic Hose Fittings, EX Series
HYDRAULIC HOSE FITTING, BARBED, CRIMPED, SWIVEL, 37 ° ELBOW, JIC, FEMALE, 9/16
Parker SV, Bulkhead Unions for Metric Tubing