The RS790 first stage combines a fully sealed, chrome-plated marine brass body with TUSA's balanced diaphragm design for reliable performance in demanding conditions. The diaphragm membrane isolates the internal mechanism from surrounding water, keeping out contaminants like salt, sand, chlorine and pool acids that would otherwise cause corrosion and mineral buildup. TUSA takes this further with a Dry Ambient Pressure Chamber, preventing cold water from resting against the diaphragm and chilling the air passing through. A strong choice for divers who regularly dive in cold, sandy, or otherwise less-than-pristine conditions and want long-term reliability with minimal maintenance.
Features:
- All-chrome-plated marine brass construction
- Balanced diaphragm design, fully environmentally sealed
- Diaphragm membrane isolates internal mechanism from surrounding water
- Prevents corrosion and mineral deposits from contaminants (salt, sand, chlorine, pool acids)
- Dry Ambient Pressure Chamber prevents water ingress into the main spring cavity
- Reduces cold-water cooling effect on air passing through the first stage
VIDEO CONSULTATIONS NOW AVAILABLE: We're bringing our highly experienced and knowledgeable staff to you with live-streaming consultations. If you need help choosing the right bit of kit or the best size before buying or even advice on whether a purchased item is the right fit for you, then book yourself a consultation appointment.
We offer free tracked UK standard delivery on orders over £50 (Excluding Weights and Cylinders, as they must go on a separate service to your order)
Standard UK delivery and Next Business Day UK delivery rates are calculated at checkout and offers a number of courier options for maximum convenience to you.
International shipping rates depend on items, shipment weight and destination. Shipping costs are calculated at checkout.
Estimated delivery times are shown during checkout and reflect your chosen delivery method. More Details
60 Day Stress Free Returns
If you change your mind, it doesn’t fit, or you become inflicted with buyer’s regret - that's OK!
Mike's Dive Store offer an extended returns policy of 60 days - so you can be rest assured if the suit, piece of diving equipment or gift doesn't suit then just send it back, and we will either exchange it or offer a full refund less any postage costs. Too easy!
Please note that there are some special order items on our website that will be subject to a 20% re-stocking fee, but we will let you know about these items before we 'special order' them so that you are aware of this. If this is the case we can always help with correct sizing so that we minimise the risk of return. More Details
Returning To Chiswick Store
We want to make your shopping experience as seamless and enjoyable as possible, even when it comes to returns. That’s why we offer hassle-free returns at our Chiswick store. But there’s more—when you visit to make a return, you can also pre-order items to be available for collection. This means we’ll have a range of sizes ready for you to try on, ensuring you find the perfect fit before leaving the store.
Shop with Confidence, Wherever You Are
To make things even easier, we offer complimentary video consultations with our expert team. Whether it’s before or after your purchase, our specialists can guide you through sizing, fit, and styling—all from the comfort of your home. It’s like having your own personal VIP shopping experience, tailored just for you.
From returns to reorders, we’re here to help you find exactly what you need with zero stress.
Book Video Consultation: Book Now
We offer the option for customers to choose ‘Pickup in store’ as a shipment method, allowing your order to be picked up from our Chiswick store at a time and date that works for you (within our business hours). The process is really easy, but we'll run through it here:
Step 1 - Add products to your cart:
Browse our vast selection of diving and snorkelling equipment, adding the kit you want to your cart.
Step 2 - Head to your cart:
Click on the cart icon to see a summary of the items you are about to purchase.
Step 3 – Review Your Order and Proceed to Checkout:
Once you're satisfied with the items in your cart, you can add a note to your order under the "Order Summary" section if desired. When you're ready to proceed, simply click "Checkout" to complete your order.
Step 4 - Customer Information:
If you have a Mike's Dive Store account, simply log in to autofill your details. If not, enter your email address, select ‘Pickup in Store,’ and then click ‘Continue to Payment’ to proceed.
Step 5 – Payment & Billing Details:
Select your preferred payment method and enter your payment information. Below, provide your billing details. If you're logged into your account, please double-check that your billing and contact information are up to date.
Step 6 – Review Order:
After entering your payment details, click ‘Review Order’ to proceed with placing your order. You will receive an email confirmation with your unique order number. We will notify you when your order is ready for collection, usually within 4 hours or sooner during our opening hours (Monday to Saturday, 10 AM to 6 PM). Please note that our hours may vary during the Christmas and New Year periods.
Our London Store Information:
Address:
Mike's Dive Store, 113 Power Rd, Chiswick, West London, W4 5PY
Telephone:
Local: 01202 037162
International: 0044 1202 037162
Email:
All Enquiries - support@mikesdivestore.com
Store Opening Times:
Mon - Fri: 10am - 6pm
Sat: 10am - 5pm
Sun: Closed
Need Help?
Our expert diving team is here to assist with your order, sizing, or product selection. We're divers ourselves, ready to support you!
Chat Hours:
Monday - Friday: 09:00 AM - 05:50 PM GMT
Prefer a call back? Just request it through the chat bubble!
Store Location
Mike's Dive Store
113 Power Rd, Chiswick, West London, W4 5PY
Store Hours
Mon - Fri: 10 AM - 6 PM
Sat: 10 AM - 5 PM
Sun: Closed
Bank Holidays: Store & Warehouse Closed (no dispatch)
Online Video Consultations
Unable to visit us? Book a live video consultation for tailored advice on equipment, fitting, or specialized gear. Get expert guidance from our team, face-to-face. Book Now
For more answers, visit our FAQs.