1.It is sealed with stainless steel 2.sturdy &durable 3.rust-resistant and corrosion-resistant 4.MINI DS1990A, 5.smaill size

smart button SMC1990A-F4 is ds1990a compatible,which size is more smaller. It  is sealed with stainless steel,sturdy &durable,rust-resistant and corrosion-resistant.

smart button SMC1990A-F4 , DS1990a compatible

1.It is sealed with stainless steel and stainless shell,sturdy&durable,rust-resistant and corrosion-resistant.

2.The quality is very good, it is durable and sturdy.

smart button SMC1990A-F4 , DS1990a compatible