A modified tube-style belay device, the Mega Jul is a passive assisted braking device.
The Mega Jul is a versatile device that provides passive assisted braking, double strand rappelling, and it has auto-block capabilities (though you'll hurt your elbows using it in that mode).
The Mega Jul is a passive assisted braking device. A clever slot in the side of the tube body causes the rope to tightly pinch between the device and belay carabiner to provide extra braking strength. This assistance is stronger in most applications than a classic tube but not as powerful as the active assisted braking devices, like the Petzl GriGri. Compared to the Mammut Smart Alpine, our testers found the Mega Jul's catch to be more confidence inspiring and stronger at locking off when a climber is already hanging on the rope. Additionally, unlike the Smart Alpine, the Mega Jul is reversible and can be used as a standard tube device when a fall is unlikely.
The performance of the Mega Jul is highly dependent on the carabiner used. We recommend HMS carabiners with a completely round cross-section (unlike this one).
Depending on how you orient the Mega Jul it can operate as a standard or assisted locking device while lowering or rappelling. In standard mode, with the green loop facing towards you, it operates like any other tube. Switch it around into assisted braking mode, and you will have to apply upward pressure on the green thumb loop for rope to feed through. Cease this pressure and the Mega Jul is designed to lock, making it easier to clean gear or undo tangles during a rappel. Although we like this feature in theory, in practice it requires that you engage your shoulder and can exhaust those muscles during long descents.
During rappels face the green thumb loop away from you and the Mega Jul claims a unique ability to auto-lock. We found this to work in our testing, but it is not without downside. Feeding rope in this position requires upward pressure on the thumb loop that can quickly fatigue your arm/shoulder.
Feeding slack with the Mega Jul is a similar motion to any tube device. It's assisted braking ability, however, requires you apply upward pressure on the green thumb loop to keep the device from locking up while paying out rope. This mechanism creates more resistance than a basic tube but is easier than the other passive assisted braking device we tried, like the Mammut Smart Alpine and Black Diamond ATC Pilot.
The Edelrid Mega Jul rigged for a top rope or lead belay. In this configuration it will provide some braking assistance but feeding rope will require an upward tug on the green thumb loop.
At 2.5 ounces, the Mega Jul is lightest of the assisted braking options and only 0.3 oz heavier than the lightest auto-block belay device, the Petzl Reverso. Size-wise it's also very svelte, with the main tube assembly among the smallest of all. Its wire attachment loop is on the large side, but how important is that really? Not much.
At 2.3 oz the Edelrid Mega Jul is the fourth lightest belay device tested and the lightest assisted braking device.
Auto-block (resistance belaying a second)
The biggest problem we have with the Mega Jul is the friction it creates in auto-block mode. It had the greatest resistance by far under the parameters of our test. It's also very carabiner dependent, and we noticed a 35% difference between the best and worst biners we tried—the Petzl Attache performed the best and is what we used in the official test.
The above diagram is from the Edelrid Mega Jul manual (downloaded 2/1/2016), describing how to belay a second climber from an anchor. Getting this correct is a bit tricky. Here's the text from the manual: "8. Securing a top rope climber from a fixed point (e. g. a station): One or two top rope climbers may be secured independently (be sure not to confuse the ropes!). The securing device must be attached at the fixed point by means of the attachment (Fig. 8a). The rope slings are fed through the rope slots and are then attached to a second karabiner (brake karabiner). Attention: The brake karabiner must be attached to the securing devices on the side opposite to the wire bracket and must directly contact it (Fig. 8b/8c). When securing a top rope climber with a single rope, the carabiner must be attached to the rope loop and through the device (Fig. 8d) instead of attaching it to the rear of the device only as when securing with two ropes (8b/e)." Please consult your Edelrid manual and follow the instructions carefully, as their recommendations may have changed.
During a long multi-pitch route you can expect to waste significantly more energy using this device to belay off of an anchor than with any other device, including a simple Munter hitch. On the bright side, the Mega Jul does better with skinny twin and half ropes, so if you're mostly using those you might not notice the friction as much.
The Mega Jul set up in our tests of belaying a second climber from an anchor (Auto-Block). Note that this configuration is a bit tricky, and it is crucial that you read the manual carefully. The configuration differs for belaying one climber vs. two, so use caution to make sure you have it set up properly.
The versatility of the Mega Jul means it's suitable for a variety of applications. At its low price, it can be an affordable option for sport climbers seeking braking assistance, though we preferred the new Mammut Smart 2.0 for those purposes. Some alpinists are also touting the combination of a Mega Jul and standard auto-block device (ATC Guide or Reverso) shared between partners. With this arrangement, the second can belay the leader with the Mega Jul's assisted braking. When the leader builds an anchor, they bring the follower up in the ATC's standard auto-block. Then, the partners swap devices and repeat. This way both leader and follower are always belaying with braking assistance and when it's time to go down there are two devices capable of two strand rappels.
The most sensible way to belay two followers at once is with an auto-blocking tube style device. The Edelrid Mega Jul was our favorite for skinny twin or half ropes.
At $40, the Mega Jul is very affordable for a belay device with auto-block and assisted braking modes. We also believe the stainless steel construction improves its durability, further enhancing the value.
We were initially impressed with the promise of the Edelrid Mega Jul. This is a light, compact belay device that offers assisted braking functions at a fraction of the price of the competition. Ultimately though, the performance of the passive braking assistance is a significant compromise from active assisted locking devices like the Petzl GriGri. It's just not as smooth or as strong. Furthermore, the Mega Jul's friction in auto-block mode was horrific. We're intrigued by the future potential of passive assisted braking devices but aren't yet willing to recommend this one over the competition we saw.
Other Versions and Accessories
The Mega Jul is designed for ropes between 7.8 and 10.5 mm in diameter. Its smaller cousin is the Edelrid Micro Jul for skinny twin and half ropes from 6.9 to 8.0 mm. Edelrid also makes a passive single-slot model called the Jul2 and an active assisted locking device called the Edelrid Eddy.