Having a metal body can be a trade off since metal is naturally heavier than plastic. However, the Rai Solo weigh only 19 grams (9.5 grams each), which is remarkably light, considering the 12 Classics IEMs weigh 90 grams!  Total weight of the Rai Solo, including the cable, it's 30 grams.The Meze Rai Solo include a 1.3 meter long earphone cable made with silver plated litz wiring, gold-plated 3.5mm connector and standard mmcx connectors that allow you to detach the cable from the earphones.
Having earphones with detachable cables means you can always replace them when they break and, you can also replace them with a 2.5mm balanced cable when using a headphone amplifier with balanced output. Balanced cables tend to be better overall because they pick up less noise, although they aren't as versatile since most audio gear uses standard 3.5mm jacks. The other detachable IEMs variant you typically get is IEMs with 2-pin connectors, which protrude more than mmcx connectors and also run the risk of reverse polarity since you can easily plug 2-pin cables upside down. Two pin cables can easily break too, although mmcx connectors do have the downside of potentially wearing out quicker because of the snapping connection, which is also an advantage as it makes detaching mmcx cables easier and quicker. The Rai Solo silver plated litz cable gives the cabling a cool white look, that is different from the steampunk style copper plated litz cables. The Rai Solo cable weighs 11 grams and, just like other litz cables, it is individually insulated by the strand and braided too, which minimizes oxidation and prevents the cable from tangling.
The Rai Solo cable does not integrate a remote control, other than a rubbery y-splitter and cinch for cable management, as well as stiff silicone ear hooks, which keep the earphones secure onto the ears.
The Rai Solo mmcx connector plugs are made of rubber, which softens the contact against the ear. The 3.5mm connector plug is also rubberized with a shielded translucent plug design reminiscent of a king cobra hood. 

The rubber plugs are a nice touch for extending the longevity of the Rai Solo audio cable since regular audio cables with plastic plugs can easily break, specially when you accidentally step on them!
Aside from the uncommon driver membrane design, the Meze Rai Solo integrate unique custom 9.2mm dynamic drivers with low impedance (16 ohms) and 105dB high sensitivity. The Rai Solo have a slightly bass-oriented sound signature with forward midrange (vocals) and slightly recessed treble sound.
The included leather hardshell travel case weighs 45 grams and has a clam shell concealed zip opening that open up via a single metal slider. The travel case has a Meze metal alloy brand tag recessed on to the top of the case. 

There is also a short fabric lanyard cord. Internally, the Meze travel case is lined with felt-like material and features a single elastic mesh pocket to organize the included ear tips. The external dimensions are 12cm long, 9cm wide and 4cm high (3cm high internally)
A selection if wide bore ear tips are included too, namely 3 pairs of bowl ear tips, 3 pairs of standard bi flange ear tips and 2 pairs of smaller bi flange ear tips for deeper insertion. You can buy the Meze Rai Solo from amazon. Check out the review of the 99 Classics headphones, 99 Neo headphones and 12 Classics V2.