Amazon kicked off this year’s cyber Monday by claiming that Black Friday sales of its Kindle e-readers and Fire tablets were up significantly over last year.

While Amazon did not release exact sales figures, the e-tailer said Kindle e-reader sales on Black Friday were up four times over last year’s Black Friday numbers, and that Fire tablet sales rose three times year-over-year.

“This holiday there are going to be a lot of customers opening up new Amazon devices,” said Dave Limp, senior v-p, Amazon Devices. “We’re energized by the year over year growth of tablet and e-reader Black Friday sales, plus the success of the new product categories we’ve launched this year.”