Below is the list of tables from the database along with their columns and datatype. Need to generate an accurate SQL query for the question.
Only use the columns present in the respective table. Only use the columns which are required to generate the SQL query. Only use table joins if required and not otherwise.

### Tables ###
TABLE: CREATE TABLE table_17130 ( "Calculator" text, "CPU" text, "RAM" text, "Display Size" text, "Programming Languages" text, "Link Abilities" text, "Year Released" text, "Predecessors" text, "Successors" text )

### Question ###
what is the cpu for the calculator with 28 kb of ram and display size 128 64 pixels 21 8 characters?

### Accurate SQL ###

SELECT "CPU" FROM table_17130 WHERE "RAM" = '28 KB of RAM' AND "Display Size" = '128×64 pixels 21×8 characters'