Binary variable length string

Hello,

I am new in PostgreSQL. My problem is that I don't know how to create a
table
with a binary variable length string.

I don't know what is the correct type in PostgreSQL  and how to make the

sql sentence.

i.e.:

create table mytable (id  ??????); -- I want a binary string

insert into mytable (0x00 0x01 0xAF); -- Binary data ????

Thanks in advance

Sorry for my English.