Darkening caps for suction cups of insulated window covers VW T4

Stop light from entering through the suction cups holding the window cover.

Loved the insulated window covers we got from
https://www.bus-ok.de/T4-Isotherm-Set-innen-Thermomatten-fuer-Fahrerkabine-91-98-Top-Qualitaet for our VW T4. 

But had the issue that a not trivial amount of light entered through the suction cups holding the window covers to the windows. Really interfered with our sleep and coziness level. To make things worse the suction cups were held by translucent white plastic ring that dispersed the light.

These cups solved the issue, as can be seen on the photos: They slip on without having to remove the metal ring attached to the suction cups.
 

Great for sleeping in on a summer day!