This is a reasonably decent (> 75% claimed) power bank given its physical size, capacity, and overall features. It's fairly small and compact in comparison to others with similar capacity. In fact, it's amongst some of the smallest ones rated at 5000 mAh. I've seen so many others with grossly overinflated advertised capacity claims and this is towards the lower end of the bunch but it still legit unlike others where they are just outright fake capacity.≡ NoteIf you see some weird, made up, or arbitrary capacity such as this 12500 or others with 13800, 15800, 16800, 25800, 26800, or 30800; chances are those are either counterfeit or fake batteries (do you see the pattern here?) and I'd suggest you take a closer look at them first (as I've found out the hard way).Those fake ones do NOT have quick charging (PD/QC 2/3) of any sort. If you see some large capacity power banks that offer 3-4 ports with LED while doesn't support QC or PD, I'd probably avoid 'em or at least look for a warning signs. I have recently come across a power bank that's only about 1/4 of advertised capacity which is just infuriating to me and this power bank restores some of the lost confidence.*** Btw, when a power bank charges faster than your ordinary wall charger is NOT THE SAME as quick charging or fast charging as some people are confused about the terms. In order to have QC, it needs to be able to provide at least 15W @ 5V, or any voltages higher than 5V (i.e. 9V/12V/15V/20V).Your phone saying it's charging fast is NOT the same as quick or fast charging.###Its battery capacity is 5000 mAh (18.5 Wh, assuming 3.7V) which sits at around the absolutely minimum capacity by today's standard; however, it's also amongst one of the smallest out there. Of course, it also supports quick charging protocols which should be the minimum supported at the moment. It has a built-in Lightning connector which eliminates the need for a cable and can be directly attached to your phone. It also has a foldable stand but I probably wouldn't rely on that especially in the portrait position because that might damage (long term) the Lightning port on your phone.It supports the most popular fast charging protocols such as QC2/3 and PD3. It supports up to 18W (9V/2A) to charge itself and up to 20W (9V/2.2A) to charge iPhones/any Apple products utilizing Lightning (PD3) ports. Keep in mind that the built-in Lightning connector is for OUTPUT only while the USB-C port is for INPUT ONLY. I wish the USB-C can be used for output as well which would've made this much more useful and versatile.≡ Specs & Build* Battery capacity: 5000 mAh/18.5.0 Wh* Input USB-C: QC/PD 5V/2A, 9V/2A (18W)* Output Lightning: QC/PD 5V/3A, 9V/2.2A (20W)* Dimension: 79 x 37 x 28 mm* Charging time: 1.55hrs (9V/2A) ***I've conducted thorough tests to determine the TRUE BATTERY CAPACITY and related info; they are summarized below.##################################################≡ Battery Capacity Tests - DISCHARGINGTime elapsed: 3 hrs 24 minTrue battery capacity: 14.30235 Wh (77.31% of advertised 18.5 Wh, higher is better)* 5.0V: 2.86047 Ah* 3.7V: 3.47895 Ah (assumed 90% conversion efficiency)≡ Battery Capacity Tests - CHARGINGTime elapsed: 1 hr 33 minTotal power provided to battery: 19.10313 Wh (103.26% of advertised 18.5 Wh, LOWER is BETTER; this is usually around 120% on average)* 9.0V: 2.122573 Ah* 3.7V: 4.64671 Ah (assumed 90% conversion efficiency)##################################################≡ ValueAll things considered, this is a reasonably decent power bank with 77% of advertised battery capacity in comparison to most others I've come across (3+ dozens) in the past year alone. It is what I'd say is a slightly above average (>75%) power bank which isn't too bad but could certainly be better (especially one from VEEKTOMX because most of the power banks from them (that I've tested) are rated at around 80%. This is one of the lower ones from VEEKTOMX that I've seen (have about 9+ from them).Based the combination of discharging and charging tests and their average percentage, the included battery (most likely a 18650) is around 4514 mAh (16.70 Wh). It has a 4303 mAh (15.91929 Wh) battery as an absolute minimum assuming it's 100% efficient which is impossible today. If it's indeed a 5000 mAh battery as advertised, then it's an exceptionally good quality battery because it has a 103% tested capacity (see tests results above) while most other decent batteries will consume about 120% due to energy loss which is unavoidable.In short, it's reasonably decent if you are looking for a small capacity power bank. Its true capacity of 3479 mAh (14.30 Wh) is certainly nothing to write home about but it gets the job done and the overall PHYSICAL build quality is rather good. It's somewhat reasonably priced at $35 for what it provides and its overall build quality.