If K-9 refers to a dog what does K-6 refer to?

K6, or Baltistan Peak, is a notable peak of the Masherbrum Mountains, a subrange of the Karakoram mountain range in Pakistan. This is probably the most famous of things that are known as "K6".

https://en.wikipedia.org/wiki/K6_%28Mountain%29

K-6
This refers to divisions of school levels. "K" meaning kindergarden "-" meaning up to and "6" meaning the 6th grade. In other words, K-6 refers to kindergarten through sixth grade. Another FAQ Farmer says that K6 means PRE NOVICE SENIOR and K5 means PRE NOVICE INTERMEDIATE. More broadly, K6 refers to events, activities, teaching or the study students in Kindergarden through 6th grade.
http://www.faqfarm.com/Q/If_K-9_refers_to_a_dog_K-6_refers_to_what
Incididentally, K-9 is not an acronym or abbreviation. It only refers to dogs because it looks cooler than "canine."

K6 or K-6 may be:

1. K6 (Mountain) mountain in Pakistan

2. AMD K6, a computer microprocessor

3. K-6 (Kansas highway), a state highway in Kansas

4. Sonata in C for Keyboard and Violin (Mozart) was the sixth work by Wolfgang

5. Amadeus Mozart according to the Köchel catalogue.

Transportation:

HMS K6, a British submarine
USS K-6 (SS-37), a 1914 United States Navy K-class submarine
Ka 6, a glider manufactured by Alexander Schleicher GmbH & Co, Germany


https://en.wikipedia.org/wiki/K-6