Power Players were available in Canada at ESSO gas stations. After purchasing a minimum amount of gas you would get a pack. To open the pack you had to tear the strips on each end. When opened cards were arrange in two rows of three. The cards were perforated for easy separation.
Cards are 1 1/2" by 2 1/8" and are generally blank backed. The exceptions appear to be cards found in the middle of the top row. These have a ESSO logo on the back. There are blank and "ESSO" backed cards for some players.
For $.79 plus tax you could get a soft cover "NHL Power Player Saver" to stick your cards or for $4.95 plus tax a hard cover "NHL Power Player Album". The Album had more features including team histories and pictures of the arenas. The Saver and Album contained gummed sheets to stick the cards in the album/saver.
At the end of the season you could order stat sheets showing 1970-71 stats for all players so you could stick the stats under the player's card in the album/saver