The BCA Aluminum Crystal Card provides a surface to analyze/classify snow grains and also has a slope index, which allows you to determine slope angles from a topographical map. This small yet very informational tool will take your snow safety skills to a new level. With the BCA Aluminum Crystal Card, you can expect durability and long-term use. BCA designed its snow study tools in conjunction with North America's most experienced avalanche educators. BCA snow study tools allow you to gather all of the data you need, without breaking the bank.