Today I received a Prova 903 multimeter that I ordered a few days ago on eBay from Canadian company that sells test equipment.
I do have a good bench multimeter the Wavetek model 52 but I wanted something more portable and the Prova looked realy good on paper and was on sale at a good price.
It is a 60000 count 0.03% DC voltage accuracy and has dual channel so you can do two measurements at the same time with just one multimeter.
Unfortunately my unit at least is not in spec on DC voltage range at least for small DC voltage. The current and resistance seems to be fine from my limited testing.
There is very little info about this multimeter and I was not able to find any review other that an older small post on here on EEVblog forum with photos form the lower end model Prova 803 that seems to be fairly similar except is missing the RMS to DC converter.
So I took a few photos with the internal to share here and I was also able to remove the black paint on the main IC to read the part number.
So the main IC is the FS9704B here is the spec
http://www.ic-fortune.com/upload/Download/FS970X-DS-42_EN.pdf then there is a high precision RMS to DC converter since this is a true RMS multimeter AD637
http://www.analog.com/media/en/technical-documentation/data-sheets/AD637.pdfAnd the other relevant IC is the DG419DY
https://www.vishay.com/docs/70051/ dg417.pdf this one probably used to switch between channel 1 and channel 2 allowing for the dual measurement option (just a guess since I did not had the time to look in details).
I have a voltage reference and in the photo you can see the measurement for the 5V actual reference voltage 5.00210V and as you can see on channel 1 it measures 5.0089V that is way out considering 0.03% spec for the DC voltage and channel 2 is measuring 5.0079V again way out. I added my Wavetek in a photo that shows 5.001V but flickers between that and 5.002V (is just a 30000 count so no extra digit at this voltage).
Same higher reading I can see on 2.5V, 7.5V and 10V
No idea if this can be calibrated easily will need to maybe contact the seller or manufacturer but it may need some special equipment.
The two large ceramic fuses are rated at 1A for the mA and uA range and the large one is rated at 20A and I tested with 12A and it seems it can measure and display that with 1mA resolution but you can only go to 20A for a few seconds not continues above 10A (to much heat).