Ping pong bat vs table tennis racket - what is the difference ?

[Moon Lobber]

A ping pong bat is a pre assembled bat or paddle. From the old days it could be just a racket with no sponge, but with a sheet of rubber with pimples on it & this bat is called hardbat. Then there are also sandpaper rackets ,which consists of two sandpapers stuck on either side of wood.

After the introduction of sponge at top level at World Championships in Bombay in 1952, sponge era table tennis was born

Modern table tennis is played with high technology table tennis rackets.

In North America where there essentially is no formal table tennis compared to Europe & Asia , it is mostly a basement "game" of ping pong
Most of these hackers use hardbat or sandpaper bats. Increasingly more players may be using lower quality factory assembled sponge rackets that you can buy in department stores or sporting goods stores.

However, even in North America , even the lowest level tournament player does not use a factory pre assembled table tennis racket.
They buy the wood part & the sponge rubber part separately & assemble the racket (or glue the rubbers) to the wood part themselves.
Why do this ? Because the wood part, popularly known as blade (or frame as in some European countries ,as in the frame of a tennis racket) is not just one piece of wood only but is a complex multiple layers of wood and space age technology composite material.
The blade alone could cost as much as $400 in 2023
The rubber itself Is also equally complicated as it also consists of two parts , the sponge side that is glued to the blade & the top-sheet which is glued to the sponge in the factory. The top-sheet is the rubber but the whole sponge & top-sheet is referred to as rubber.
The glue that connects the rubber to the blade is the most controversial aspect of tabletennis since late 70’s & won’t be discussed here. Highest professional players may change their rubbers for every one or two matches.
The rubber on one side of the racket alone could cost as high as about $90 in 2023
A high end bottle of glue could cost about $40
So a high end player assembled table tennis racket could cost as high as $620 ( $400+$90+$90+$40)
But you could assemble a decent (lower level) tournament quality racket for less than $100

[Cobie]

Here is a clear explanation of top sheet & sponge as components of a table tennis "rubber" from revspin .net

topsheet and sponge