UNO Slam

Uno Slam is one of many variations on the popular Mattel card game Uno. It includes 108 cards as well as an electronic Slam unit, with a big red button and two card holders. The main difference from the original Uno is that every time you play a card, you have to slam the big red button.

—user summary

The UNO button is SLAMMED to start a race against the clock. Each player in turn attempts to play one card from their hand by matching either colour, number or symbol. After their turn they must quickly SLAM the UNO button before the 'BOING' sounds.
If they fail, they must add another four cards to their hand. Players must remember to shout "UNO" when they only have one card left.
The UNO SLAM unit has adjustable times for different levels of play. This new and exciting way to play UNO will give hours of tantalising hun for all the family.

—description from the box (1996 First Edition)