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Description
Description
The Hollis 500SE + DC7 DIN is a regulator pairing a proven first stage with a servo-controlled second stage for scuba diving gear. The 500SE second stage uses a servo-controlled valve to provide airflow control suitable for air and trimix dives in a side-exhaust configuration. Built for backmount and sidemount setups, this regulator pair emphasizes reliable performance across demanding diving conditions.
The DC7 DIN first stage delivers high performance with an over-balanced design that maintains stable intermediate pressure as depth and gas density increase. Fixed hose routing supports both backmount and sidemount configurations. Environmental sealing helps prevent internal corrosion, contaminants, and icing. It is designed for coldwater performance under CE standards, Nitrox compatibility to 40%, and offers 2 High Pressure ports and 4 Low Pressure ports with DIN/300 bar compatibility.
The 500SE second stage features a pneumatically balanced servo valve system for consistent airflow. It includes a patented orthodontic mouthpiece for comfort and reduced jaw fatigue, and comes with a 30 in. maxflex hose. The unit is easily disassembled without tools, and can be serviced underwater if necessary. It supports left or right positioning with a boltsnap tie point and a side-exhaust design for practical use in diverse diving configurations.
Features
Features
- DC7 FIRST STAGE High-performance over-balanced design; fixed hose routing; environmental sealing; coldwater CE standard; Nitrox compatible to 40%; 2 High Pressure and 4 Low Pressure ports; DIN/300 bar.
- 500SE SECOND STAGE Pneumatically balanced servo valve system; orthodontic mouthpiece for comfort; 30 in. maxflex hose; tool-free disassembly; left or right orientation; boltsnap tie point; side-exhaust configuration.
- System design and compatibility Ideal for backmount and sidemount scuba diving; suitable for air and trimix scenarios; designed to work within scuba diving gear ecosystems.
Specifications
Specifications
DC7 FIRST STAGE
Payment & Security
Payment methods
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WARNING: This product contains chemicals known to the State of California to cause cancer, birth defects, or other reproductive harm. For more information, visit www.P65Warnings.ca.gov.
Frequently Asked Questions
How often does a scuba regulator need servicing?
Follow the interval in your regulator's manual, since manufacturers commonly specify an annual inspection or a set number of dives and many warranties depend on it. A regulator is life-support equipment, so service belongs with a factory-trained technician rather than being attempted at home. Have it looked at sooner than scheduled if you notice increased breathing effort, free-flow, bubbles, or water in the second stage.
How do I rinse and care for a regulator after diving?
Make sure the dust cap is dry and firmly seated over the first-stage inlet before the regulator goes anywhere near water, because water inside the first stage is the leading cause of internal corrosion. Rinse in fresh water without pressing the purge button, since purging while depressurized can draw water back into the second stage. Shake out the water and hang it to dry with the hoses in wide, gentle loops rather than tight bends.
Can I fly with a scuba regulator?
Regulators travel well and are usually best carried in hand luggage where they will not be crushed or lost. A regulator holds no gas of its own, so there is nothing inherently problematic about it on an aircraft, though the airline and security screeners always have the final say. Pack it dry with the dust cap in place, in a padded regulator bag or wrapped in soft gear.
Can I use my regulator with nitrox?
Many modern regulators are supplied as suitable for nitrox mixes up to 40 percent oxygen, which is the widely used recreational industry standard, while anything above that requires dedicated oxygen-clean equipment and procedures. Confirm what your specific regulator's manual states, and follow your nitrox training and your fill station's requirements. Never assume a regulator is oxygen-service clean simply because it looks clean or is new.
What is the difference between DIN and yoke regulators?
A yoke (A-clamp) fitting clamps over the tank valve and is the most common connection across much of the recreational world, while a DIN fitting screws into the valve and is standard in much of Europe and in technical diving. DIN captures the o-ring inside the threads, which many divers consider more secure, but yoke is often what rental cylinders provide. Adapters exist in both directions, so check what is used where you dive before deciding.
What is the octopus regulator for?
The octopus is your backup second stage, carried so you can share air with a buddy who is out of gas, or breathe from it yourself if your primary fails or free-flows. It is normally on a longer, brightly colored hose so it is easy to find and hand over under stress. Secure it in the triangle between your chin and the bottom of your rib cage so it is instantly accessible and not dragging through sand or coral.
How should I store a regulator between dive trips?
Store it fully dry, out of sunlight, with the dust cap in place and the hoses in wide loops rather than tightly coiled. Avoid hanging it by the second stages for long periods, which stresses the hose fittings; laying it flat in a padded bag or hanging it by the first stage is kinder. If it has sat unused for a long stretch, have it checked before your next trip rather than assuming it is ready to dive.
