My cousin gave me my first Chinese abacus. There were no manuals attached, and so I did not know how to work it. I later bought two smaller ones, of differing sizes and gave one away. The small one I had left somwhow got lost during house moving. Recently, I discovered it after some tidying up. I am now starting to learn how to use it because it has an accompanying instruction booklet with it.
The first abacus has a wooden frame, wooden beads, both a very dark brown colour, almost a shade of black. It has strips of brass pieces which helps to keep the rigidity of the structure. The beads are threaded with cane rods, which are pale in comparisson to the frame and beads. There is a little sign on the frame wchich says that it is a Lotus Flower Brand, and "Made in the People's Republic Of China". The frame has dimensions 28.7cm by 14.0cm by 2.2 cm, with a spacing of the rods at 2.0 cm, and bead height approximately 1.0 cm, and 1.7cm at its widest bulge. There are 13 rods in all.
My second abacus is much smaller, but correspondingly much heavier. It is made of brass, and set upon a dark green marble slab. I do not know its origins, except, on the box, it says, Brass Abacus, and "Original Chinese IBM". The dimensions of the slab are 13.8 cm by 5.8 cm by 1.1 cm. The length of the brass frame is 13.0 cm, with 4.6 cm width. There are 15 brass rods with brass beads, the height of 5 beads is 1.8 cm, each bead is 0.6 cm wide at the bulge. The rods are spaced at 1.8 cm.
I am currently using the larger one to work with, since it is more finger accessible.