8300mAh size is DC5521, 9V 1A/11Ah size is DC5525, 5V USB 2A/20Ah. 9V DC output suitable for Guitar Multi-Effects Pedal Processor and more. But most guitar pedal input port is inner Negative(-), outer Positive(+).
Nice battery pack. Plastic but solid. Compact for power rating with lots of charging options.
Perfect so far. Does the job with power and time to spare. I made a cable (had to reverse polarity) to power a 9v mini guitar amp and multi-effect pedal (pic) so the practice rig is mobile for travel and busking. Charging phones and tablets is a nice bonus.
I like the 9v has a different connector (2.5 pin) than the 12v (2.1 pin) so it's harder to make a mistake even though it's clearly marked (and jack is a different color). Nicely done guys.
Haven't used it a lot, not sure how many charges and I haven't cracked it open to see if the batteries are replaceable but I hear they are good quality so we shall see.
Thanks for reading.