These rotary unions are designed for the passage of coolant, air, MQL, and dry running. The semi-integrated mounting within the spindle allows operation under heavier conditions compared to self-supporting unions. The use of a special seal design enables the spindle to operate dry without opening the seals, eliminating any fluid loss caused by the continuous opening and closing of the seals. The compact, lightweight design (anodized aluminum) enables these unions to operate at high rotation speeds (up to 40,000 RPM) and high pressures (100 BAR).