KPrepublic Novelty Backlit Keycaps - Chinese Internet Slang 

SPEC

• thick ABS plastic
• OEM profile
• R1- 1U, R1-2U, R3-2.25U
• Laser-etched pattern
• ESC row and Enter

屑, pinyin as XIE (the fourth tone), original means like fragments. Now, it has the Internet meaning rubbish and sucker.  

摸鱼, pingyin as Mo(1st tone) Yu(2nd tone).  It is from a Chinese 4 characters Chengyu (idiom) '浑水摸鱼', which means to get advantages in a confusing situation. In the Chinese Internet, Moyu means to get leisured when working. 

RNM退钱, it is a punchline from a football match.  Nowadays, it is an expression that you think something you paid isn't worth it. It is similar with 'Fxx, return my money' in English.