The most common and most likely answer to this crossword clue is the 9 letter word BACKBOARD
B
A
C
K
B
O
A
R
D
More clues leading to the result BACKBOARD
Buddy explains!

The straight part
We know that "rigid product" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case rigid product = backboard.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does BACKBOARD mean?
BACKBOARD noun- The flat vertical surface to which the basket is attached.
- A flat vertical wall with the image of a tennis net drawn or painted on it. Designed to practice hitting against such that the ball bounces back.
- (first aid) A spine board.
- A board placed at the back of a cart, boat, etc.
- The port or larboard side of a ship