How do you condense ipv6 address?

To condense an IPv6 address, you can omit leading zeros in each 16-bit block and replace contiguous blocks of zeros with a double colon (::), but this can only be used once in an address. For example, the address "2001:0db8:0000:0000:0000:0000:0000:0001" can be condensed to "2001:db8::1". This makes the address shorter and easier to read while maintaining its uniqueness.