Exactly what I needed. The eraser does erase cleanly and without any smudges or stray marks. The lead is perfect for writing small print math problems on college-ruled paper. Here is my lead breakdown:
0.3 mm - Perfect for writing as small as possible on note cards or note sheets for exams (cram as much information as possible on the permitted note medium). Difficulty: this thin diameter lead breaks with minimal pressure. I go through a lot of lead when writing exam note cards so this diameter is not recommended for regular use. This was a common size for engineering/drafting years ago.
0.5 mm - The lead size in this product. PERFECT for someone with decent hand pressure control or someone who has plenty of extra lead on hand. The pencil writes fine while still being sturdy enough for my creaky hand.
0.7 mm - Sturdy, but writes very mushy. Fine for writing words and doodling and probably acceptable for higher-level math on wide-ruled paper but gets a little "squishy" fitting equations on one line of college-ruled. I find myself frequently rotating the pencil or even intentionally breaking lead to try and find a sharper edge.
0.9 mm - Perhaps fine (and even preferred) for younger students but 0.7 mm is bad enough for higher-level math that I'd never use this lead.
I've included a photo that compares the 0.3 mm, 0.5 mm, and 0.7 mm pencil leads (I do not own a 0.9 mm pencil) on standard college-ruled paper. The 0.5 mm example demonstrates a pencil from this set. The comparison should be enough to determine which thickness is right for you. I also erased and rewrote one of the numbers on this example, using the eraser of this particular product. As you can see, it erases very cleanly. See if you can guess what was erased!
Long story short: Excellent pencils with fine lead and quality erasers for CHEAP!
Each BIC pencil provides write-out equivalent to 2 1/2 woodcase pencils. Shatter- and splinter-resistant. Each pencil is filled with three 2 leads. Perfect for standardized tests. Mechanism: Mechanical Pencil Type: Mechanical Lead Colors: Black Barrel Colors: Assorted.