This small but confusing set has been an interesting puzzle for collectors trying to figure out its secrets. First, there are three types of the regular TV-type cards: Type 1 features a faux-television screen on the front, with woodgrain border, while on the back is featured a 'TV Knock-Knock' joke. Type 2 features the same front, but blank backs. Type 3 features salmon-colored borders around the front image, as well as blank backs. The Type 1 cards are also numbered 1 to 55, while the other Types are not. This is misleading, as only 22 cards have been confirmed in the entire set: 1, 2, 4, 8, 9, 12, 16, 17, 20, 22, 28, 30, 35, 36, 37, 41, 43, 45, 47, 50, 53, and 55. This type of 'skip-numbering' can be found with some older sets, as deceptive card companies sought to keep kids buying packs in order to get numbers they didn't already have.
In addition to these, there were also two other sets of 'bonus' cards, each numbering 22: 'Knock-Knocks' and 'Ton O' Laffs' cards presented more jokes for the buyer. (Were these distributed in smaller numbers, such as one of these to a pack?) The individual Knock-Knock cards duplicate the backs of the Type 1 cards mentioned in the previous paragraph. These cards have salmon borders on the front and black backs also. (A few cards with red borders are assumed to be Canadian issues.)