Lens Ports This housing features Ikelite's robust Dry Lock (DL) port system. "Dry Lock" refers to the placement of the o-ring on the outside of the port mount. This improves visibility and reduces the chances of water dropping onto your precious camera sensor. DL ports are the lightest on the market, yet robust and capable of standing up to rough surf. Attachment is quick and secure. A system of extensions can accommodate a huge variety of lenses with ease. Most popular zoom lenses and select lens focus rings can be engaged using simple gearing that puts adjustment right at your fingertips. A large, soft-touch knob on the side of the housing makes fine tuned adjustments a breeze. Zoom and focus gears differ depending on which lens you are using. Zoom gears sold separately. View the DL Port Chart for Nikon Z-Mount... Vacuum System The included vacuum valve allows you to pressurize the housing to check for leaks prior to putting your expensive equipment in the water. Use of the vacuum valve requires a compatible Vacuum Pump with Gauge # 47011, sold separately. There is no greater assurance than being able to see your camera and o-ring seal through the back of the housing. Ikelite's signature open-groove design suspends the rear o-ring in a natural position that is easier to maintain and more reliable than forcing the o-ring into a channel. Once the housing is closed you can see the o-ring form a solid, waterproof seal. M16 Accessory Port The spare M16 threaded accessory port provides an attachment point for third party accessories including HDMI bulkheads. TTL Exposure This housings supports your choice of shooting manual strobes or adding TTL electronics depending on your application. The included manual hotshoe with Ikelite ICS-5 bulkhead supports manual strobe exposure with a wide variety of strobes including Ikelite, SEA&SEA, INON, and others. You can enjoy the fastest and most accurate TTL exposure on the market by adding the DL1 DS Link TTL Converter # 46056 and a compatible Ikelite DS strobe. The DL1 supports rear curtain synchronization and exposure compensation can be added or subtracted in the camera. Controls and Set-Up Shutter and AF-ON levers stand out with super sensitive and natural feeling curved levers.  Both controls can be extended using the optional Trigger Extension # 4077.95 for more comfortable use when using a right-hand quick release handle. All push button controls are machined and hard anodized aluminum to reduce weight and resist salt build-up. The back of the housing is laser engraved with control symbols which will never fade or fall off. The camera mount is front-loading for easy installation and removal. A small mounting plate attaches to the bottom of the camera and secures in the front of the housing. The camera mounting plate does not need to be removed from the camera for surface use or when changing the battery or memory cards. The mounting plate features a 1/4-20 threaded mount on the bottom so that it can be attached to a tripod on the surface. Viewfinders The included Super-Eye Viewfinder provides an enhanced view of the camera's optical viewfinder when viewed through a dive mask. The viewfinder removes quickly and easily for the attachment of an optional Straight Magnified Viewfinder (Type 2) # 6890.1 or 45° Magnified Viewfinder (Type 3) # 6891.3. The angle of a 45º viewfinder is more ergonomic when shooting underwater plus it provides a larger and brighter view than the standard Super-Eye. Handling & Travel The housing, tray, and handles have been optimized to reduce weight while maintaining strength and durability. The Right-Hand Quick Release Handle # 4077.02 (sold separately) can be added or removed depending on your needs. The precision machined aluminum base features 1/4-20 tripod mounting sockets and additional mounting locations for future accessories. The base and handle can be quickly removed when breaking down your system for travel. A 1/4-20 threaded mounting point is located front and center on the housing above the lens port mount. This mount can be used to attach lightweight accessories like a focus light or GoPro camera. If you're shooting with two strobe or lighting arms, then a top handle can be added to carry to and from the dive site. Top handles are available in a Cable Grip # 4080.09 or Aluminum Top Handle # 4080.08. The rigid aluminum version provides additional mounting points for lighting and accessories. Adding a dedicated focus light to your top mount or strobe arm is highly recommended for more accurate autofocus in low light settings. Construction Ikelite's new ABS-PC blend front is durable, provides improved contrast and visibility, keeps your camera running cooler in the sun, and is significantly lighter weight than aluminum alternatives. Every housing is made in the USA, individually inspected for fit, and water pressure tested to  60m (200 feet).