These shofars are Rarely available in these lengths. All of these quality shofars are Certified as suitable for mitzvah blowing by Israel's Chief Rabbinate.
With practice, anyone can evaluate how to really blow the Shofar. One who blows the Shofar is known as a Baal Tokea, or Master Blaster. in hebrew" It is exceptionally strenuous to blow the Shofar on days of distinguishment. Then again, an extraordinary blaster in the service understands that blowing the Shofar is for all intents a holy trust that arouses the congregation.
On the Jewish festival of Rosh Hashanah, the Shofar is blown 100 times to initiate the New Year. It is similarly blown at the end of the Yom Kippur organization to imply that this day of penitence is at a successful end.
Shofars of this type are also used in the worship by many Christian denominations on Pentacost and Tabernacles festivals.