The Gemini Mini Dab Rig is MJ Arsenal's double-ball concentrate rig — 6.5 inches of premium borosilicate over a base-connected puck percolator, on a 10mm joint. An inverted cone base keeps the water volume low, a splash guard sits between you and the chamber, and it ships with a quartz bucket and flat carb cap at $54. It is the taller, smoother end of the mini-rig line.
The name describes the build. Two stacked chambers give the Gemini its silhouette and its function, splitting filtration across a pair of volumes rather than asking one chamber to do everything. Vapor passes the puck percolator at the base, moves through the first ball, then the second, and reaches you having changed direction several times. Each transition costs heat and adds contact with moving water, which is the entire mechanism behind a smooth pull.
The result at 6.5 inches is closer to what a much larger piece delivers, without the footprint.
The puck percolator is the piece of engineering worth pausing on. A puck sits flat at the base and disperses vapor across its full width through many small holes, rather than concentrating it through a single downstem opening. Wide dispersion at the very bottom of the water column means vapor is broken up before it has travelled anywhere — the most efficient place to do it.
Connecting the puck directly to the base, rather than hanging it off a removable downstem, also removes the joint most likely to break on a rig this size.
The inverted cone base solves a problem specific to small rigs. Concentrate vapor is easily over-diluted, so you want as little water as possible doing as much work as possible.
A cone that narrows downward concentrates the water into a small volume at the bottom while keeping the surface area needed for the puck to work, which is why MJ Arsenal frames it as preserving terpenes — less water and a shorter path means less of the flavor gets stripped on the way through. Practically it also means less to pour out, less to refill, and less to slosh.
Three details show this was designed by people who actually use rigs. There is a splash guard, which on a piece with this much water movement is not optional — double-ball filtration is energetic, and without a guard the energy arrives at your mouth. There is an oil catch beneath the receiver, so residue collects somewhere you can reach rather than migrating into the chamber, which meaningfully lengthens the interval between deep cleans.
And the mouthpiece is angled, so the rig can sit flat on a table while you use it rather than requiring you to lift and tilt. Combined with the flat bottom, the Gemini is stable in a way tall-necked small rigs frequently are not.
Who this is for: concentrate users who found the smallest mini rigs too harsh and full-size rigs impractical. The Gemini occupies the space between — enough filtration to be genuinely smooth, small enough to leave out on a table without it becoming furniture. The included quartz bucket and flat carb cap mean $54 covers a working setup rather than the first half of one, and quartz is the material worth having if flavor is the reason you are running concentrates.
Who it is not for: anyone wanting maximum portability, or flower. At 6.5 inches this is a stay-at-home piece, and it takes a 10mm concentrate joint, not a bowl. If you want smaller, the Hydra Mini Dab Rig runs a recycler at 4.5 inches. For rolled goods, the Martian Blunt Bubbler is the piece. Nearby in the same line sit the Titan Mini Dab Rig and the Hydros Mini Rig, and the full catalog is at MJ Arsenal.
Material is 100% premium borosilicate throughout, which on a multi-chamber piece is a requirement rather than a selling point. Every chamber transition is a place where thermal stress concentrates, and soda-lime glass develops stress fractures at exactly those junctions over time. Borosilicate takes the temperature swings — hot vapor, cold water, isopropyl cleaning cycles — without accumulating that damage. On a rig you intend to use daily for years, the material choice is the difference between a piece that survives and one that eventually fails at a seam.
MJ Arsenal was founded in Denver, Colorado, and names innovation, affordability, and functionality as its operating pillars. The Gemini is a reasonable test of that claim: puck percolation, double-ball filtration, an oil catch, and a splash guard describe a rig that would have carried a three-figure price from most of the market a few years ago. Pricing it at $54 with the bucket included is the part that actually matters, and the brand's patent and trademark filings suggest enough of the market agreed to be worth defending against.
The wider point is that mini rigs stopped being the budget option and became the informed one. Concentrates reward a short vapor path and a small chamber, so building down was never a compromise — it was the correct answer that the culture took a while to accept while it was still scoring glass on height. The Gemini is what it looks like when a brand designs for the actual physics and then refuses to charge boutique prices for it.
Specs
- Brand: MJ Arsenal, Denver, Colorado
- Type: Mini dab rig
- Material: 100% premium borosilicate glass
- Dimensions: 6.5in height x 3.75in x 2.75in
- Joint size: 10mm
- Percolation: Base-connected puck percolator with double-ball filtration
- Design: Inverted cone base for low water volume, splash guard, oil catch beneath the receiver, angled mouthpiece, flat bottom
- In the box: Gemini Mini Dab Rig, Mini Rig standard quartz bucket, flat carb cap, digital care guide
- Price: $54 direct from MJ Arsenal
For legal adults 21 and over.