Belgium Item Help Needed

Found this item today, and even though I am not sure what the heck it is, it looks official and a keeper. Any of you have any ideaas?
The date is 1909 or there about.

OK, figured it out myself, with a little help from Google translate...
This is a cover for the following event:

MUNICIPAL AUTHORITIES OF BRUSSELS
ANNUAL TRADE FAIR
ORGANIZED BY THE CITY OF BRUSSELS UNDER THE PATRONAGE OF HM THE KING
WITH ASSISSTANCE OF THE GOVERNMENT AND THE PROVINCE OF BRABANT.

In the lower left corner "FREE POSTAGE"

Brochure addressed to:
BELGIAN SOCIETY OF BALL BEARINGS S.K.F.

This was in French. And from what I can determine a SKF Ball Bearing is some particular type of bearing.

Oh well, as mentioned above it is a neat item, I will keep it.

As mentioned the postmark is either 1889 or 1909, hard to see as it was co vers with
somekind of ink (grease?).

I may be corrected but certainly during the 1970's
SKF ball bearing races, were one of the best and most reliable
races around, sold in most major automotive shops
in Australia.
Bearings for motor cars, trailers, drive trains, you name it.
Almost a "household" automotive name.

A typical SKF packet
this time with a roller bearing

Interesting, Rod222. Ball bearings are a field I know very little about, other than if they come undone you are in trouble. Thanks for the info. I will print this out and keep it with the item. This is why I enjoy postal history collecting, one never knows what one can learn each day.

SKF bearings were sold in Auto Parts shops in Canada also in the 80's and 90's, maybe even now, yes, where you have to now replace the whole bearing assembly on front wheel drive cars.

Thanks for input Puzzler...Guess they have been making these things for a long long time...