Ultimate Guard Boulder Deck Case Review

Ultimate Guard Boulder Deck Box Review

Written by Jon

5 minute read

The Ultimate Guard Boulder is one of the best known small profile deck boxes in the TCG world. It is so loved and recognisable that Ultimate Guard have now made an accessory supporting version called the Boulder ‘n’ Tray. It is safe to say the Boulder’s simple yet recognizable design has stood the test of time but has that been justified, or should you be giving it the cold shoulder as it gets older? 

How is the build quality of the Boulder?

One of the most appealing aspects of the Ultimate Guard Boulder is the almost unbreakable, rock-solid design. The 2 pieces of the box are made of 3 - 3.5mm thick plastic, with the sides being slightly thicker than the front and back, that even when unassembled are challenging to bend. The plastic is translucent with a fogged, soft-touch film coating that adds a stylish matte sheen to the surface and allows for spying which cards are stored inside without having to open the box.

Not only does the Boulder Deck Case provide a safe space for your cards during transport, the compact design means the 2 near symmetrical halves sit neatly together on your gaming table without taking up too much space, with the Boulder ‘n’ Tray offering a detachable accessories tray to boot.  

A black Satin Tower separated and then mixed with a pink Satin Cube

The Boulder and Boulder 'n' Tray can be deconstructed into 2 and 3 separate parts respectively, to be customised at will.

Crush-proof, lightweight and modularly customisable with other Boulders, the build quality is spot on and toughness is second to none. The Boulders are also fantastic looking deck boxes, available in a wide variety of colours with countless possibilities to mix and match halves. Fantastic work from Ultimate Guard, both the Boulder and Boulder ‘n’ Tray are a 10/10 for build quality and toughness.

How many cards does the Ultimate Guard Boulder fit?

Ultimate Guard claims the Boulder 100+ can fit 100 double-sleeved cards when sleeved in their own Ultimate Guard sleeves. However, not all sleeves are created equal and in such a varied market of brands in 2023, a deck box must be more versatile than that to get the job done.


Looking closer, we measure the storage compartment of both the Boulder and Boulder ‘n’ Tray to be 68.3mm which equates to being one of the smallest storage spaces of any 100+ deck box we have come across. Unsurprisingly, this space will struggle to fit 100 double-sleeved cards in some of the thicker sleeves available on the market such as the popular Dragon Shield Mattes, and any speciality inner sleeve such as the Gamegenic Closeables or Ultimate Guard’s own Resealable Precise Fit Sleeves. To see exactly which sleeves will fit into the Boulder 100+, please visit our detailed Deck Box Comparison Tool.


If you do not require room for a 100 card deck, the Boulder also comes in a 40+, 60+, as well as an 80+ size, all with the same build quality and design as the 100+. However, the Boulder ‘n’ Tray is only available in the 100+ size.

Is this the Ultimate Guard to secure your cards?

The Boulder utilises a nub and dimple mechanism for locked closure, similar to the Ultra Pro Satin Cube. This takes the form of 4 small dome-like nubs and 4 opposing dimples, but unlike the Satin Cube, it is combined with 2 larger sets of nubs and dimples, leaving absolutely no doubt about the strength of the closure.

A closeup of the nubs and dimples of the Boulder

The network of nubs and dimples that create the locking mechanism of the Boulder.

As with all of our deck box reviews, we commence a shake test which consists of filling the Boulder with 100 double-sleeved cards and shaking it with increasing degrees of force in an attempt to open it and spill the contents. It is here where the Boulder shines brightest. No amount of shaking even comes close to beating the incredible closure offered by the locking mechanism and we can confidently award a full 10/10 for security.  

Is there anywhere to put accessories?

The Boulder is a simplistic deck box and has only the one compartment for cards. If you require room for accessories then the Boulder ‘n’ Tray is the answer.

The aforementioned tray measures 6.83cm x 6.91 cm x 3.4 cm = 160.46cm3. This is the biggest accessories tray of any deck box in the 100+ category and deep enough to store the oversized spin-down dice found in Magic: The Gathering. 

The dimensions of the large accessories tray

The accessories tray is the biggest of any in the 100+ deck box category.

A very minor point is that the Boulder is not a perfect square but it’s also not immediately obvious which side is longer. This can cause minor confusion when putting the tray back with the rest of the box. We would also advise to take care when detaching a tray full of dice as the closure is strong.

How much does the Ultimate Guard Boulder Deck Box cost?

The price of the Ultimate Guard Boulder depends on the chosen capacity. We sell the 100+ for around £9, the 80+ around £6, with the 60+ and 40+ being even cheaper. The Boulder ‘n’ Tray comes at a slight premium at £11 - £13.

The prices of both 100+ options are priced to be competitive with their main rivals - the Satin Tower and Satin Cube. As always, prices vary over time and between vendors so please do your own research on price!

Closing Thoughts

The Ultimate Guard Boulder remains one of the most prominent deck boxes on the market; and for good reason. The toughness and security of the Boulder is unrivalled, and the simple design is timeless. Whether in storage or in transportation, you can count on this deck box to protect your cards.

Where the Boulder falls short is the restrictive amount of space for 100 double-sleeved cards. More than 7mm smaller than its closest rival the Satin Cube / Tower, the diminished space is really noticeable with many combinations of inner and outer sleeves struggling to fit. We would advise checking our comprehensive Deck Box Comparison Guide to see exactly what will fit into the Boulder before buying to avoid any unwelcome surprises.

Build Quality and Toughness 
68.3mm - struggles to fit 100 double-sleeved cards in thicker combinations
Security 10/10
Accessories Boulder ❌, Boulder 'n' Tray ✔️
Price Boulder £5 - £9, Boulder 'n' Tray £11 - £13

That being said, the addition of the Boulder ‘n’ Tray to the range excites us and gives us hope that this great product will continue to be updated by Ultimate Guard over time. We have everything crossed that Ultimate Guard can take a page out of Gamegenic’s book and create an XL version of their beloved product. If they do, we can’t see choosing anything else over it. 

Double Sleeved was founded in 2019 by Andrew and Jon, two lifetime card game enthusiasts with the goal of providing amazing prices, service, and creating helpful content for the community. Today, we are one of the best rated TCG stores on Trustpilot with 98% of customers giving us a perfect 5 stars!

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