No person wants to be kicked at full power so we have a variety of boards with different strengths - You can use these to practice and improve your technique and be sure that your kicks are truely effective - These boards are terrific value because they have a shaped joint so that you can put them back together and keep using the board for 20 or 30 years -- SIZE - This solid Black board is the "standard" 28 x 28 cms square and 2 cms thick -- STRENGTH - Because the boards are made in a machine the strength will always be the same - BUT the strength of wood can vary and this Black Board is approximately equal to a dry piece of Parana Pine that is 50 mm thick -- ADVICE - There is nothing worse that not succeeding so we recommend that you start with a lower strength board and progress to stronger boards as your technique improves -