You can buy compasses at will. There are no taboos. It should be noted that when the Feng Shui compass is not in use, it is best to lay it upside down so that the magnetic needles will not be damaged. If the compass is placed casually, it will cause problems with the compass and make it unusable.
Compass Tianchi is also called the seabed, which is the compass. The Tianchi of the compass is composed of a thimble, a magnetic needle, a seabed line, a cylindrical outer box, and a glass cover, which is fixed in the center of the inner disk. There is a pointed thimble in the center of the bottom of the round box. There is a concave hole in the center of the bottom of the magnetic needle. The magnetic needle is placed on the thimble. The arrow-headed end of the compass points south, and the other end points north.
There is a red line drawn on the bottom of Tianchi (the seabed), called the seabed line. There are two red dots on both sides of the northern end. When using it, the north end of the magnetic needle must coincide with the seabed line.
A modern compass has cross lines drawn on the sea floor, and the tops of the cross lines are printed with southeast, northwest and north respectively. When using it, the north end of the magnetic needle should point to the north end of the cross line on the sea floor, and the magnetic needle should coincide with the north-south lines on the sea floor.