Standard Postcard-a standard postcard mails First Class at current rate of 35Â¢. The smallest maiLabel size for ANY postcard is 3Â½â³ x 5.â³. The largest postcard size for mailing at the 35Â¢ rate is 4Â¼â³ x 6.â³. The paper thickness must be at least 0.007 â³ and not more than 0.016 â³ in thickness.
1 Prohibits head first diving in water depths less than 8 feet. 2  Restricts use of starting blocks to competitive swimmers or swimmer training activities.  Requires new installation (effective October 7, 1992) of starting blocks to be in the deep end in at least 6 feet of water.
With standard scuba equipment you have a maximum depth of approximately 60m (195ft). This is because, after this depth the pressure exerted on the oxygen in your air supply becomes toxic, going further or experiencing this toxicity for too long could prove fatal.here are specialised pieces of scuba diving equipment that make it possible to overcome deep diving problems such as nitrogen narcosis, oxygen toxicity and the tremendous pressure you can face at extreme depths.